Coolant leak and slow speed fan not working
 

Hi All,

When I last posted about the coolant leak it was suggested that I bypass the oil cooler which I have done but there has been no difference still loosing a small quantity of coolant. The thermostat has been replaced the inlet manifold gaskets have been replaced with a coating of Hylomar there is no leak at the water pump or in the V.

I tried a test suggested on here, i.e. take off expansion tank cap run the car cold for about 10 seconds at idle and then accelerate up to the red line, if coolant shoots out of expansion tank this confirms HGF. I did this but no coolant shot out of the expansion tank. Is such a test conclusive or not?

I discovered today that the slow speed of the coolant fan is not working, could this cause coolant loss and do I need a new fan?

Any assistance will be gratefully received. I should mention that the car is a 2003 MG ZTT KV6 with 60,000 approx miles.

Martin

Yes.
No. You can repair it. Is it a 2 or 3 speed motor?

Simon

Thanks Simon. I don't know whether it is a 2 or 3 speed fan. I can't see a resistor therefore I suppose it is 3 speed in that case wouldn't I be better off replacing the whole fan with a new 2 speed one. On the V8 you have to cut the shroud to clear the aircon pipes I know this because I have just fitted one. I assume it is the same for the KV6 or can you just swing the shroud out of the way to get to the fan motor?

Martin

In my view, no you wouldn't. My reasons for saying that are:

• A new 2 speed system is expensive. A set of brushes for your 3 speed cost £20.
• You don't have an unreliable resistor to worry about with the 3 speed.
• The 2 speed is noisier than the 3 speed.

You will read posts which say that it is, but with a bit of ingenuity and by taking my time I managed to re-brush my 3 speed fan motor without cutting the shroud. :D

If you do decide to replace rather than repair, perhaps you'd consider offering your removed 3 speed to Arctic.

Simon

Hi Simon,

On closer inspection it is in fact a 2 speed fan with a resistor. The high speed is working therefore I suppose it is either the relay or the resistor that is faulty. What do you think please?

You said previously that if the low speed fan is not working this is responsible for the coolant loss. Where do you think the coolant is going?

Martin

Hi Martin. Is it a silver coloured resistor? If so, it will be that.
On a 2 speed system with a failed resistor the fan will not start running until the coolant has reached 112 degrees. Not only is that much too hot, it is only three degrees below the temperature at which the temperature gauge rapidly swings to the red line and you're officially overheating. You also run the risk of the expansion tank cap venting to relieve the pressure with consequent coolant loss which will probably leave little or no trace.

But don't get bogged down in theory Martin. You have identified a fault with the cooling system and it needs to be repaired immediately. You can then reassess the situation.

When the thermostat was replaced, who did the work? If you did it yourself, did you refill and bleed the system afterwards by raising the expansion tank and by following the MGR procedure exactly? If not, this can cause problems with coolant level.

Simon

Hi Simon,

I decided for peace of mind and quickness to replace the complete fan after all the fan motors do have a tendency to pack up at between 60 and 80k . MGOC are doing the Chinese ones apparently off the production line for £175 plus postage better than Rimmers for £300 plus postage. They were quick to send me one and I have fitted it, so I will now have to wait and see if it has cured the leak. Personally I am rather pessimistic and I still think it is HGF but will report back in a week or so.

Incidentally I have had the car for 16 years and have changed the coolant on a number of occasions and I always adhere to the procedure set out in the Haynes manual.

Martin

I regret to say that my worst fears have been realised. I had to add about 300mls today after travelling only about 20 miles. I have had a good look underneath and there is no sign of any coolant and the v is as dry as a bone. There does not appear to be any coolant on the dipstick and the oil level seems okay in spite of the amount of coolant loss. I would have expected the level on the dipstick to have risen.

I am now at a loss as to where the coolant is going. It is looking increasingly like HGF but I don't know how to prove it. Do you think I should drain the coolant and refill it very carefully? It is very strange because the car is running perfectly.

Martin

It isn't Martin. Where's the evidence? What event would have caused the alleged head gasket failure? No, it's a variation in coolant level, the cause of which hasn't been found yet.

300 ml of coolant is not a lot. If it's seeping out of a failing thermostat housing 'O' ring it can evaporate quickly leaving little or no trace. You could leave your engine acoustic cover off for a while and check frequently for coolant with a powerful torch both when the engine is running, hot and cold, and when it's not.

On the straight pipe, are the two plastic clips pushed fully outwards in their channels?

But I'd say that the most likely reason is unintentional errors made during the refilling and bleeding process:

• The Haynes manual can be misinterpreted. The small bore air bleed hose entering the expansion tank neck should not be disconnected.
• It is essential that the expansion tank is raised during the refilling process.
• The bleed screw should be refitted before starting the engine.
• The engine should not be run with the bleed screw removed under any circumstances.

Another common cause of slight coolant loss is worn seals on the expansion tank cap. They can be obtained separately, there's no need to buy a new cap.

Simon

Hi. I had the same problem last week and the mechanic diagnosed HGF it's easy to proove using a special instrument with inside a blue liquid that need to be putted instead of the water tap.. If the liquid become green that's HGF. Good luck!

Caution
 

Matt's car overheated. He was advised to first check his radiator fan but he chose not to. Against the advice of every member who replied to his thread, he put Steel Seal :devil: into his cooling system based only upon a mechanic's highly controversial diagnosis.

The KV6's gaskets are not susceptible to spontaneous failure. I would never place total faith in a mysterious liquid which changes colour without firm supporting symptoms and Matt didn't have any.

Simon

Thanks Simon. The evidence may be the mayo in the cap although this may be due to the fact that the car is not being used much. The thermostat was very carefully replaced and yes the two clips on the straight pipe were pushed right up either end.

I left the cover off for a couple of weeks to inspect the v periodically and there has been absolutely no leak.

I thought that the expansion tank cap has three seals. Is it sufficient just to change 2?

As a last ditch attempt to avoid having to lift the heads I am going to drain the coolant, reconnect the oil cooler, sort out the expansion tank cap and then carefully refill the system as recommended by MGR. If it then continues to leak the heads are going to be removed as I can't put up with a car that leaks coolant.

I will keep you posted!!!

Martin

:iagree:

When I renewed the two 'O' ring seals on my expansion cap it cured the varying coolant level. :}

When you drain, don't forget the LH bank cylinder block plug.

Simon

Since my last post I have been away. I have now changed the seals on the expansion tank cap and I have drained the coolant and refilled it very carefully, also refitted the oil cooler pipes. Last Friday drove about 75 miles on checking the level the following morning it was ok so I thought I had cracked it, alas that was not to be. On Sunday drove 35miles and when I checked the level this morning it needed about 400mls to bring it up to the correct level. It looks like HGF. Any other suggestions or tests I should run to confirm?

Martin

Ztt kv6
 

Hello Martin,

I have found that following refilling and bleeding, it's necessary to 'top up' the expansion tank two or three times before the level stabilises. This might be what you're experiencing. If you continue regularly to lose amounts like 400 ml then you must have a leak. Before you say that you haven't, they are very difficult to identify. I have similar loss from my SD1's expansion tank at the moment apparently with no trace. However, when lying under the car to carry out an unconnected repair I noticed a single drop of coolant clinging to the bottom of the crankshaft pulley. The likely source of this is the water pump bearing because it has a drain hole directly above. Clearly, more coolant than a single drop is being lost, but the remainder is dispersing as the car is driven (or there may be a second point of loss which I haven't spotted yet).

You don't have head gasket failure Martin. You have declared no symptoms of it. What you have is a coolant leak. I suggest that you support your car on axle stands, crawl underneath with a powerful torch and carry out a slow and careful inspection for signs of coolant residue. In the meantime, just keep topping it up.

Simon

Get yourself a dentists mirror too. That engine gets very warm and any escaping coolant not finding a nice little recess to accumulate in will evaporate quickly leaving a pale pink residue which can easily be confused with the normal oxidisation of the metal components.

I've had coolant leaks as a result of the following (all mercifully fixed now): compressed thermostat housing O-rings, incorrectly positioned thermostat straight pipe fixings, expansion chamber cap O-rings, cracked plastic elbows on the radiator, failed inlet manifold gaskets and of course good old perished coolant pipes.

In many of these cases what you're trying to see is cunningly concealed behind or beneath what it may be leaking from as a result of gravity and water's natural tendency to cling to suitable surfaces as it makes its way down.

Or of course it could simply be as Simon suggests and your cooling system has accumulated a lot of air bubbles

Martin,

Have you fixed the absent low speed fan?

Yes he has (Post no. 7 Ken). ;)

Simon

Thanks for the responses boys.

Simon, I put the car on a 2 post lift and had a good look underneath before I refilled the system and could find no evidence of a leak. I will for the moment continue to top it up and hopefully next week I will have another look underneath, I have a telescopic mirror.

I'm afraid I am beginning to loose faith, after all this problem has now existed for nearly a year!

Martin

have a look under the expansion tank before you refill to check if it has a minor leak and slip on an extra jubilee clip if not sure. also at the opposite end on the top of the radiator elbow is another known point of weeping. try carefully to retighten the elbow onto its oring or renew with a metal one. these are two items that cured a very similar coolant loss on my kv6 many years ago. keep searching you will find the cause eventualy.

Well. folks it's still leaking! I did a gas test which proved negative i.e. the liquid stayed blue.

I have put it on a two post lift again and checked thoroughly but no sign of any leak. I left the engine running for about twenty minutes as well, still no visible leak.

I note Trickey on here knows a member with the same situation but who had a respected garage change the head gaskets but the car continued to leak.

There is some mayonnaise visible when you remove the oil cap but I put this down to the fact that the car is not being used very much. There is no coolant on the dipstick.

I don't know what to do next apart from removing the heads and changing the head gaskets. The car is no good with the leak so I think this is the last ditch attempt at solving the problem. Any other suggestions please?

Martin

Perhaps a long shot but I'll mention it anyway. My daughter's 75 came with a leaking hose (bleed screw one) that the previous owner had "fixed" with some pipe and two jubilee clips. It still weeped, so I replaced it. Couple of days later daughter phoned, please tow me home - car overheating. Traced it to another leak, but this time the other large hose from the thermostat - took a while to find as it has a kind of sheath and it leaked from inside this sheath.

Good hunting

Here's something from earlier ...
Simon

A leak from heater matrix pipe inside the car?

There is nothing for it other than to take the heads off and replace the head gaskets. I will have to choose my moment as I have to work outside. It will take me about two weeks but I will not be working on it full-time.

I will report back!

Martin

Have you had a pressure test carried out on the cooling system?

:wot:

When i have had leaks thats the first thing i do - up on ramp engine on and undertray off - done it twice in 6 years - first time she was running for an hour when the leak was spotted from the IMG - leaked only when really hot - 2nd time a few minutes - the small turbo hose had become loose as the clip had failed.

Martin,

I have reviewed the evidence you've provided which is relevant to a head gasket failure. Please read through your own words again:
It's not exactly overwhelming evidence of a head gasket failure is it. The KV6 gaskets are MLS not the elastomer type originally fitted to the 1.8 engine. To damage an MLS gasket on a KV6 would require, for example, severe and sustained overheating.

In respect of the "some mayonnaise" you've reported present in the left-hand bank which you put down to infrequent use, if I were in your shoes I would seek to test that theory. A dose of Comma 'Flush Out' flushing oil may remove the emulsified oil but I could not give you a guarantee. Why don't you take the car for a long journey (several hours) and check that the coolant is reaching normal operating temperature by using the built-in instrument pack diagnostics. You should see temperatures in the low to mid nineties, rising to 100 degrees when subsequently stationary in traffic.

One thing which doesn't appear to have been mentioned is the coolant level in the expansion tank. Are you observing the tab labelled 'max' within the tank? If not, it will be overfilled and will eject the excess.

Martin, your plan to remove both cylinder heads in the open air is born of despair and not from the evidence available and reasoned analysis. It is an enormous job involving a timing belt change which should not be undertaken lightly and I just don't see the evidence to justify it.

Simon

Simon.
I have read through this thread today and half way through i was thinking maybe to much coolant is being put in, thus not giving any expansion so being ejected out the cap.
https://i.imgur.com/FNwNhjBl.jpg1

https://i.imgur.com/pvCdIGCl.jpg2

Please ignore if the coolant is as above in the photo's

No Steve the system has not been overfilled. Simon I take your point about evidence but I have run out of ideas as to where it is leaking. The car is only being used for short journeys as I am not too keen to take it on a long run which might then cause it to overheat. I suppose I could check the water temperature as you suggest but I doubt that is the problem but we will wait and see. Anyhow I have no intention of taking the heads off at the moment I shall wait for warmer weather. I have done the job before including stripping the heads but this time I do not intend to do that because the car has not overheated that makes the job alot easier. Watch this space!

Martin

Have you ever tried nipping up both of the alloy manifold to cylinder head set pins? The card gasket joint does lose clamping force over time. There is a coolant gallery at each end that could leak into the cylinder and not show up in the vee. Failing that remove the manifold and fit new gaskets, remember to tighten the set pins again as with heat the manifold joint will loosen.

You must be mad!
Taking the heads off without any evidence of blown gaskets?
Or have I missed someting?

I'm not mad but this is my last resort. I believe I have exhausted all the alternatives. It is just not possible for me to run a car that looses coolant so taking the heads off to inspect the gaskets has to be done even if it only eliminates it as a cause. I realise it is a huge job but the alternative is to scrap the car which I am reluctant to do. More constructive comments would be more helpful.

Martin

More constructive comments.:shrug:
My good man, this is the most constructive I can come up with at the moment.
You have NO indication that head gaskets play any role. You have two of them, and you want to remove them without ANY evidence that anything is wrong??. You have even tested for hydrocarbon in the coolant. And the results were negative!

Have you pressure tested the cooling system.?

Have you checked the two metal pipes in front under the radiator in the corners.?

There are most likely the first dozen tests a normal person would perform before the heads are removed.

But, this is your car, your money and your time. Feel absolutely free to use that anyhow you see fit.;)

Can you eliminate my question in post #31

Gary I must have missed your posts. I think you are referring to the inlet manifolds. I have replaced both gaskets TWICE so I think it most unlikely that it is leaking from there.

I have noticed that the engine oil is rather black and coupled with the mayonnaise under the oil filler cap I consider this to be sufficient evidence of a slight head gasket failure, although it does not appear to be getting worse.

It is still leaking 700ccs of coolant to about 130 miles, so now that we are in lockdown it may be a convenient time to do the job and now that we have some better weather.

I read somewhere that you do not have to remove all 3 bolts of air con compressor although it may be revealed once I start work, which two should be removed please?

I trust everyone is keeping safe in these rather bizarre times.

Martin

Mayo under the oil filler cap, just indicates water in the oil. It does NOT say anything about where it comes from!
It could be a case of little use, and not getting up to temperature. That is the most optimistic version.
Then it could be water from any little leak into the oil side, and here inlet manifolds on the V6 is right up there. So is a leaking oil cooler! I have not read through this whole thread, so it might have been said already.
Head gasket is the most pessimistic option, and should only be considered, if backed by other indicators, like hydrocarbons in coolant, over pressure or visual indicators of water in a cylinder(s).
In other words, that is the last option to go for, and one only done is confirmed by other tests.

As I've said before Martin, I disagree. Please revisit my post number 28 for the reasoning.
This most likely explains the mayonnaise under the oil filler cap. If a head gasket failure caused mixing of oil and coolant you would see it in the sump as well but not with your engine.
When it's permitted, start taking the car on long runs and yes, definitely monitor the actual coolant temperature. Avoid the temptation to dismiss anything without appropriate evidence.

Martin, renewing KV6 head gaskets is an enormous and expensive job involving, for example, timing belt renewal. Since these gaskets are multi-layer steel your engine would have to have suffered serious overheating to result in damage. Please consider this very carefully before proceeding with a strip-down. If you still decide to do it, here's the answer to your question:
Just the two at the front because they pass through a casting which needs to be removed.

Simon

I am sorry to hear that you still have this problem, but appreciate you coming back to update, one of my chief failings.

Have you drained and inspected the oil? If it is okay it can be put back.

That's interesting. Do you mean it looks unusual or that it's overdue for a change?



TC

Yes i agree - if its a car that does short journeys and low miles between yearly services i would expect golden/clear oil not black :shrug:

The oil was changed about 10 months ago and the car has only covered about 2500 miles since. I would not have expected the oil to be black. The mayonnaise is not just under the oil filler cap but you can see it inside the engine. I have therefore reached the conclusion that coolant is mixing with the oil as a result of HGF. Given the history and the fact that I cannot find any other leak there does not seem to me to be any other alternative than to take the heads off and have a look. I realise it is a huge job but I have exhausted all other avenues!

Martin

When I had similar symptoms I decided to keep on driving and topping up until something major happened - it did. I had a proper overheat and had to be trailered home. I bought a replacement second hand engine and swapped them - but I did take a look at the old one - the first symptom I missed was a slightly rusty and red-tinged (stained from OAT I reckon) spark plug. My HGF was water getting into the centre front cylinder. No Mayo, no oil and water mixing.

I'm not offering an opinion on the cause of yours - just sharing what happened to me.

My trouble started with a radiator failure - but it also appeared someone had put K-seal in the system at some point so that wasn't necessarily the root of the issue for me.

After changing the radiator, inlet gaskets, thermostat, filler cap and the pipes at the front for stainless ones and bypassing the oil cooler, I was still losing coolant so I gave up trying to find out why and just drove until something blew.

Martin, the reason I asked about "dropping the oil" was that in my mind, draining oil is simple, and once in a container one could see if there was contamination and what it is. It's a lot easier and cheaper than taking a head off.
Good luck.

Do you use OAT antifreeze? If so, I can tell you that if the 50% mixture gets into the sump in high volume and the car is driven for short while, the result is a black viscous emulsion that isn't remotely like mayonnaise.It looks more like molten bitumen. whether this effect is specific to OAT I don't know.

I'd suggest you drop the oil and take a closer look. If the above has happened, it will take days to empty due to the high viscosity. I recently had a catastrophic failure of the OEM HG due to seal delamination. The coolant was dumped into the sump. I was about 15 miles from home and risked a very slow drive back after topping up the cooling system. I couldn't believe what came out.

EDIT: I have a 1.8Turbo



TC

Well I decided to "bite the bullit" and take the heads off. What I found was that the insides of the cam covers were completely covered with mayonnaise. I have never seen anything like it before. Both head gaskets seemed to be OK so the only conclusion that I have reached is that there must be an internal crack somewhere. Where and how this could have occurred is a complete mystery but it is looking terminal.

I have to say that I had forgotten how painful this job is and for this to happen to an engine that has only covered about 63,000 miles and been meticulously maintained is really quite shocking.

Simon was right that it wasn't HGF but it looks like it is much worse.

Martin

Thank you Martin, that's very courteous of you. :bowdown: I'm more accustomed to hearing from certain quarters that my investigative nature and lifetime of successful and economic car maintenance and repair is worthless. ;)
That's interesting. Were the camshafts and valve gear similarly covered or is the mayonnaise only found on the covers? Please let me know and in the meantime I urge you not to speculate on theories such as internal cracks which can never practically be proven.

Simon

What's the oil like? Did you drain it out?


TC

Well, there you go. ASS U ME. That is what assume stands for.
Any ***** could have told you that HGF was unlikely.
Well, hang on a mo, a couple of *****s actually did!!
And now you are assuming again. You must break that habit, it is no good!

A crack. Well, while that is a possibility, it is also the least likely option in my view. I have seen/heard of one crack in a V6 block, so while possible, I would take it to be rather rare. But someone might be able to cast more light on this topic.
But there you go, you lose your head in a panic, well let me re phrase you have now lost your heads and it has given you very little until now.


And, btw. I do admire your honesty. Not many people will stand up and get counted when making a mistake.:cool:

https:imgur.com/h4Rv365/

Here is a picture of a crack on cylinder no 6 on a V6. How and why I don't know. And no, I could not get the pic to post. This crack would have been visible from the bottom of the engine I guess. Look at the white deposit on the block below the cylinder. Even after 10 years, a water leak is clearly visible as a whitish deposit on the engine casing. So, IF, you have a crack, it might be worth to check with the oil pan off.
But at the moment, the best option is a good replacement engine, I guess.

Best of luck!

The mayonnaise is confined to under the cam covers. I have not fully drained the oil but I can see it is black no doubt coolant mixing with the oil.

I have been giving this a lot of thought and I have decided to have the cylinder heads pressure tested and then see what happens. I think it less likely that the block has cracked but you never know!

I will keep you posted.

Martin

Thanks for this Martin. I think the question should be asked: why? If oil and coolant are mixing, wouldn't you expect the valve gear to be covered in it as well? :shrug: Wouldn't this be a virtual certainty if, as you surmise, there's a crack in the head as opposed to the cam cover?

How has this car been used? Does it stand for long periods outside? The cam covers are probably the coolest part so I'm wondering whether it's condensation mixing with oil vapour. Are your breather tubes intact or have they fractured recently?
Regarding this and T-Cut's post, you will need to drain the oil since he specifically states that ....
So if yours doesn't, could the black oil simply be a sign that a change is overdue?
By the way, if you have a black tipped dipstick as I do, that can mislead. Wipe it on a sheet of kitchen paper to obtain a true indication of the lubricant's colour.

As you can probably tell, it will take a lot to convince me that a head has cracked. There's always a temptation to follow a very complicated diagnostic path when most faults turn out to be very simple. Think of garages looking at a 75/ZT which overheats and convincing the owner that the head gasket has gone and the car's fate is sealed. We all know that the fan is the most likely culprit. :cool:

Simon

Martin, coolant emulsified lube oil looks like butterscotch Angel Delight, however if left long enough, it will separate out.............

Here is Kaiser's picture of the cracked block with the liner removed.

https://i.imgur.com/h4Rv365.jpg

I've seen cracked liners on a couple of occasions, and also failed head gaskets, and while certainly much less common than the four cylinder engine, not unheard of and definitely not to be dismissed as never happening ever as a lot of people will have you believe ;)

As you've now got the heads off, drop the sump remove the pistons and liners ad take a look at the block, also it may simply be a matter of resealing the liners, as it's possible for water to track between the liner and block, ending in the sump ;)

Best of luck

Brian :D

Thanks MarinaBrian.
For some reason I can't get that link to take!
Anyway, looking at the picture, I actually think that water stain is from a leaking head gasket, if I have to be honest.:getmecoat:
I cannot see how the grey plume on the wall comes from that crack. It could well have caused a problem, but I cannot see water having run down between the liner and the block, there is no corrosion further down, from what I can see. I didn't remove the liner, maybe it was also cracked, I don't know.
It looks to me as if the gasket has been breached at the corner where the waterway is, and the marking is from that, rather than the crack itself. :shrug:
Ah well, assuming, and all that jazz.:D
And, upon closer inspection, the next cylinder, no 4 below, has also cracked! Which I can't remember to have noticed before. But there definitely appears to be a small crack on that as well.
This is the block I use when I make the thermostats, and I got it in 2008, if I remember correctly. It comes in handy for making sure all measurements are correct. But there you go. Two cracks, at least.
I wonder what actually happened to that engine, to cause this. I will have a closer look tomorrow. Now it is dark, and the temperature here in Africa drops like a lead balloon after sunset in winter. no cloud cover and the heat just oozes out into the dark night sky, where, high enough, you have -270 oC.

Not in my case with a 1.8Turbo at 32K miles. It had full synthetic engine oil and a standard 50% OAT coolant charge, when the latter was effectively dumped into the former over just a few miles. I was seven miles from home and stationary when I noticed the cooling fan running. Soon after that, the gauge went asymptotic and the red light popped on. I stopped to check and found the header tank empty. Luckily, I had some coolant in the boot and after cooling down and topping up, cautiously returned home. It was very clear that the sump was full of coolant-oil mix. I saw a pale coloured emulsion around the top end. On draining down next day, there was no butterscotch mousse. It released a jet black, viscous fluid resembling tar or molten bitumin. Obviously cold, it took several days to empty.

I was therefore intrigued by the observation made by Martin about his V6 oil after only 2500 miles. However, he has yet to drain the sump to enable us compare notes. It's apparent though, that given the right conditions of oil type, coolant type/concentration, plus the homogenisation of the running engine, something rather different from the typical mousse can be produced. The cause was catastrophic delamination of the rubber seals on the OEM gasket. The gasket shown here had been washed/cleaned.

https://www.mediafire.com/convkey/6c...c8jkq27j6g.jpg

As can be seen, the fire rings are perfect and the head surface was mechanically perfect. Only the seals were faulty. Most interestingly, there was a distinct pink 'staining' on the metal around some of the seals and on the corresponding areas on the head. It appeared to have been deposited by the coolant flow around the seals and the hot fire rings

https://www.mediafire.com/convkey/d5...o9l6mmx26g.jpg

The OAT coloured stains wiped away with a paraffin damp rag. I suspect this is a typical example of the head gasket failure that's characterised this engine since birth. My personal opinion is that this particular gasket was not fit for use with OAT. The rubber to metal bonding also looks inferior by today's standards, but is clearly adequate. I have replaced it with a Payen type elastomer of similar construction and refilled the cooling system with 25-30% OAT. In fifteen years ownership, I've not had any other OAT implicated failure.

TC

That type of failure is a catastrophic mix of oil and water. That is not the same as a smaller amount ending in the oil and "burning" off.
The smaller amount will actually evaporate off the oil in the sump, and lodge itself as "mayo" in the colder areas of the engine, notably under the oil filler cap and other colder parts.
I have little doubt your fault was the OAT attacking the silicone seals. However that type of gasket was never (to my knowledge) used in the V6.
These are multi layer gaskets, and they are not prone to this type of failure.

Coolant is typically 50% water and 50% ethylene glycol. It's the water that evaporates. The glycol mainly stays put. A slower leak over a long period will generate a similar system to the one I experienced. That's what I was hoping to confirm. With sufficient homogenisation, the coolant is incorporated into the oil phase as a water=in=oil emulsion. This type of emulsion is invariably of high viscosity. In my case (and perhaps the current subject) it produced a black and highly viscous combination. I suspect the strange colour change is related to thermal and chemical effects on the OAT dyestuff and the active ingredients in the antifreeze. I've not read of a similar effect from non-OAT type antifreeze, so I assume (sorry) that this case also involves OAT coolant. However, that hasn't been reported. In my case. what little water evaporated over the short journey produced the typical upper end condensation emulsion/mayo you describe. In other areas, a less viscous greyish emulsion was also evident (see second photo above).



TC

TC that is a classic example of a post 1998 HGF model, so nine years after the engine was originally launched ;)

This is the exact reason I use antifreeze with silicates used in the role of corrosion inhibitors :)

It goes to show after replacement with a BW750 (identical to the factory fit BTW, as Federal Mogul supplied Powertrain) and a 25% mix of OAT, that there has been no repeat failure.

That ratio of coolant is advised by Jules, and he has done for years, it would be interesting to compare the hybrid OAT silicate coolants to see how they stacked up against the pure OAT formulations, in terms of elastomer seal damage.

Brian :D

Classic anti freezes have proved their worth for the last 100 years or so. It is well know they work, and also that they need replacing at 2 to 3 years.
If you do that, you have perfect protection against both corrosion and also freezing, provided you don't dilute the mix.
If that has been good enough for my grandfather who drove Fords, Taunus, Fiat and Austin, and my dad, who drove Fiat, Alfa, Mercedes, then it is good enough for me.

I have never used OAT, and I never will.

Brian I'm afraid I have no intention of removing the liners especially not with the engine in situ.

I haven"t yet had a change to drain the oil but propose to do it tomorrow. In the meantime I have had the heads pressure tested, no leaks found. I have also had the heads lightly skimmed to ensure they are perfectly flat and i have ordered genuine MG Rover head gaskets.

The head gaskets I removed were MLS and I could find nothing wrong with them. How does OAT coolant react with MLS gaskets.

Could there have been a failure of the MLS gaskets even though a chemical test proved negative?

OAT antifreeze won't have any effect on a multi layer steel gasket Martin ;)

Why not fill the jacket water spaces in the block, and see if the level drops through leakage, while you have the heads off, just a thought :cool:

Brian :D

That's a good idea Brian. I suppose I should just fill the water jacket around the block but not around the liners, is that right? If I find there is no leakage I assume that I will need to drain off some of the coolant before I put it all together. If I need to drain the block I won't be able to access the drain plug because the car is supported under the sump at the moment because the right hand mounting has been removed, what do you suggest please?


Martin

No, just fill it up until it's level with the lowest part of the liners Martin, and leave it to see if the level drops.

You don't need to drain the block, if it stays level after the test, just siphon the water out with some thin tube, I use a length of washer jet hose, but any thin tube will do.

Brian :D

Absolute disaster! I wasn't happy with the belt tension so decided to remove the belt and put it back on. The special tools went on after a bit of hassle (air con pipes again) and was putting the belt on when the tool on the rear head camshafts fell off and when I tried to put it back on the end of the exhaust cam broke off!!!!. I have seen this happen before in previous threads and was hoping that I would not experience this first hand. Obviously I do not wish to incur the expense and considerable time fitting a new camshaft so is it possible to deal the rear cams without the special tool fitted. The special tool is still fitted to the front head camshafts and I have already loosened both the sprocket bolts. I do have some markings on the sprockets and covers before I took the old belts off. Any assistance will be appreciated.

Martin

Inbox full
 

Martin, please clear your inbox. I would like to send you a PM.

Thanks.

Simon

Hli Simon, Thanks for your message I have tried to delete the messages without success. I have sent a message to the administrator.

Martin

Simon, the message box has now been cleared.

Martin

Thanks Martin, PM successfully sent.

Simon

Fitted the new camshaft then fitted the tools to the front and then the new timing belt, made sure it was nice and taut. Removed the tools fitted the secondary belts to the rear head as they had to be removed to fit the new camshaft, sprockets not quite in line as before.

Turned the engine over twice at the crankshaft bolt then fitted the front tools . Unfortunately only one would go on the other was very slightly out. Does this mean I am one tooth out with the belt which would be very strange as all my marks on the sprockets line up.

I really do not want to complete the rebuild until I am sure the timing is 100%. Any assistance will be much appreciated.

Martin

I doubt it Martin. One tooth is an enormous error and a difficult mistake to make.

Did you rotate and hold both front sprockets fully clockwise (as viewed from the front of the engine) as you engaged the new toothed belt with them?
MG Rover says it's permissible to turn the sprockets a minimum amount anti-clockwise in order to fit the drive belt.
All this is done, of course, with the front tools fitted and the camshaft sprocket bolts hand tight only.

Simon

Thanks Simon. Yes it was all done in accordance with the book. I agree that one tooth out would be difficult to achieve if it is done correctly but why won't the tools fit?

Martin

What a saga. Hope it all ends excellently!!

Fred:bowdown:

We'll need to explore a few possibilities.

Do you have the INA instructions to set-up the timing belt tensioner pulley (not included in Haynes or RAVE)?

Simon

No I don't but I doubt that is a problem because I didn't interfere with it and it was working perfectly ok before. I was thinking Haynes and Rave do not mention anything about putting the timing tools back on after the belt has been put back on Haynes only mentions that after putting on the new belt you should turn the engine over twice to see that the marks line up which I did and the marks on both sprockets line up ok. As I said when I put the timing tools back on one is ok but the other is very slightly out, should i ignore this and just proceed, what are your thoughts.

Thanks Martin

I think this is due to the tensioner taking over the responsibility for keeping the belt taut. I bet it is the rear bank that is slightly out. What you could try is bring the crank to the safe position and put the timing tools on the bank that is correct. Then slacken the bolt on the other bank's camwheel and see if you can reset that camshaft with the other timing tool. Then re-tighten the bolt. Do you have to replace the bolt with a new one? I think probably yes.The theory is that if it is due to the timing belt settling in, the camwheel will rotate slightly to accomodate the very small change in belt tension. If it won't reset it will probably be due to the fact that the camwheel is as far anti-clockwise that the keyway will allow it to move. I had this when I put my new timing belt on and decided to ignore it. However, there is no doubt that the timing on one bank is correct and the other is out by about a degree or two. That's my theory but someone more experienced and more knowledgable will have a different view. Coming back to your coolant leak.
I have been chasing a similar leak for about a week.
I found two leaks one at the elbow on the off-side top of the radiator. This was only present when I ran the engine and the pressure built up. It was cured with a new 3mm thick 'O' ring. I was then left with a leak of 100ml per 24 hours. It is generally accepted that one drop is one tenth of a ml. So I had a leak of 40 drops per hour or one drop every 2 minutes. I realised that this is tiny and the drop may well dry up before it falls or seep along some joint and evaporate. I examined every hose joint that could have been disturbed when I was working on the engine. I found that one of the clips on the oil cooler was damp underneath the clip. This was the culprit. It was undetectable until I slackened the clip just enough to see underneath the clip itself. So it appears the coolant evaporated before it became visible . That has been my recent experience and it was so frustrating and time consuming because you had to wait so long between each check on the coolant level. So I do hope that when you get around to the coolant problem again that you will be able to solve it with some similar simple remedt.

Fred

Yes Fred your coolant leak looks a relatively easy fix compared to what i have had to contend with. I have had the heads off and it is a huge amount of work. I did it about seven years ago when the cam belt snapped because of a seised belt tensioner and I must admit that at the time I said it would be unlikely for me to ever do it again but I must be a sucker for punishment. In fact it all went reasonably well until the camshaft broke and it has gone downhill ever since. I have noted what you say but I think in the end it will be better to take the primary belt off and start again and also do the secondary belts again as well, after all I have all the bits taken off so that it shouldn't take too long and I must try and get it absolutely right. I didn't have such a problem last time so I can only think having the heads skimmed has changed something. Also, last time I had someone to lend a hand and now I am seven years older and I did most of the work up till now on my own with only a little help from my wife. I have now asked a friend to give me a hand hopefully next week so that should help, I hope!


Martin

If you have a friend helping who is patient then I would do the rear belts with the heads off. That is if you have the heads off already. It is the valve springs acting on the cams that make that approach difficult. You need three arms fully available to do it!

Good luck.

Fred

This is an update to the coolant leak problem. I decided that as a last resort that I would remove the heads. It is a massive job and made even more difficult without assistance which was not readily available in these times. If I had to do it again, which I hope not, I would't do it without assistance being available. For instance, such assistance is useful because it it much easier to remove the heads without removing the exhaust manifolds and then replacing the heads with the exhaust manifolds fitted because access to the manifolds is so limited.

Upon removal of the cam covers I discovered a thick layer of emulsified oil i.e. mayonnaise! There had obviously been a head gasket leak for some considerable time, as I thought. Just goes to show that you cannot trust those chemical testers. Upon examination of the head gaskets there was no evidence of an obvious defect but when I did this job seven years ago I did not use genuine gaskets on the rebuild so there is a lesson there.

I therefore had both heads pressure tested for leaks, no cracks found, and both heads lightly skimmed. The engine was carefully rebuilt with genuine MG Rover gaskets and I found the head gaskets did not have the word "top" on them which I had not come across before, however worked out which was the correct way round.

It fought me all the way but eventually got it all fitted back together. It started immediately but rattled presumably because there was a lack of oil in the tappets but it is now running nicely. Had to top the coolant up once after it had cooled down and have now covered about 130miles with no leak!

I hope that this is now the end of this long running saga and perhaps Kaiser who said I must be mad to take the heads off will reconsider what he said!

Martin

Thanks for this interesting and valuable feedback Martin. I have never been entirely convinced by the chemical testers either. From what you've discovered taking off the cam covers and having a look is the most reliable option. Thanks also for alerting us to the perils of using non-genuine gaskets in this critical application. It's good to know that no cracks were found.

Yes, I'd say so. Mine was the same after being off the road for a couple of months.

You must be feeling very pleased with yourself Martin. :D

Simon

It's always a question of degree or concentration. These so-called 'block testers' rely on detecting carbon dioxide from the exhaust gas dissolved in coolant. In an obvious/severe case of HGF, exhaust gas will bubble continuously through the header tank, so you know anyway. In less obvious situations, CO2 has to be desorbed from the coolant and into the test solution in sufficient quantity to reduce the pH. There has to be enough to flip the colour of the indicator (due to acidity). So, a very small long term exhaust leak may not increase the concentration enough. The gas level is very low because of ongoing thermal desorbtion and venting, coolant changes, top ups and the like. Basically, the test is very prone to false negative results (as in the current case). However, it will never, ever give a false positive. Other factors also affect the reliability, like reagent freshness, the operator's competence and using reliable hardware. As with many engine issues, it's just one diagnostic among several. For me, the long term coolant loss and black oil clinched it.


TC

Congratulations.:bowdown:
Next time you remove the heads use a an engine crane. Hope you never have to though.

Thanks Simon. I did in fact send you a PM on the !st June thanking you for your assistance and moral support but on looking at the "sent messages" in my private box it seems to have vanished into thin air!

I think that the job was made a lot harder because the weather was so nice and as I have to work outside with the sun blazing down it makes it more tiring. Probably have to invest in a parasol or remove all the junk out of one of my garages. Fred, an engine crane seems a bit over the top as I only have limited room to store one what with all the other paraphernalia that I have.

I am pleased that I managed to rectify the problem because it would have been a shame to have scrapped the car as it is overall in very good condition, I bought it new and it has only covered about 63,000 miles.

The only problems left to deal with are a noisy air con compressor, I have a new one in stock, do I need to change the condenser if I fit the new one? The other problem is that the instrument cluster warning light for the oil pressure has stopped working. I have already changed the pressure switch so it must be the led. Anyone know how to change it. Any assistance will be appreciated. Once these have been sorted I am hoping that I won't have to spend too much time sorting any other problems.

Martin

Air con. & oil pressure LED
 

Oh dear, the time to have done that was during your timing belt change when you had access. :o Have you already checked that you have the correct refrigerant charge? If not, I would do that first.
That's would be very unusual. Can you easily remove the connector from the pressure switch? If so, do that and earth it. Does the LED light now? The white/brown wire passes through the underbonnet fusebox on its way to the instrument pack. There may be a poor connection there.

Simon

Thanks Simon. I have checked the refrigerant charge and it is ok. I have a very good air con man close by and will speak to him next week.

I will check the wiring for the oil pressure switch when I am next underneath the car. I agree it is unusual for the led's to fail but not unheard of.

Martin

Run the IPK self test Martin, it will identify if the LED is functional (very likely)

Brian :D

Air conditioning
 

There's another possibility to consider. When the compressor is engaged it places a significant load on the ancillaries belt. If your tensioner is not in the best of health this could be what you're hearing (diesel owners are familiar with their crankshaft pulley mimicking a problem with the air conditioning).

Is your system cooling normally?

Simon

I saw my air con guy today and it is his view that the compressor is breaking up. Although my tester said it was satisfactorily charged he said it was only air and therefore it didn't need discharging. So probably next week I will be fitting the new one which I have. He also confirmed that a new condenser would be wise which he obtained for me. It is a Hella unit so it should be good quality I will also fit that next week as well. Once it has been done I will have it recharged. It is a bit of a hassle to have to deal with this after all the other work that has been done but what can you do?

Martin

:eek: Wow!
Didn't you say that your car has only covered about 66,000 miles? I wonder what caused that?

Simon

The car has only covered about 63,000 miles. I had to replace the original because it was leaking badly. I initially bought a secondhand one for £50 put it on and it was also leaking but it has lasted two years. I bought a brand new one to replace the secondhand one because it is obvious that secondhand ones are probably a complete waste of money, that is my opinion. Much as I like the car if I have any more major trouble with it I will be getting rid of it.

So far as the oil pressure warning light is concerned I did the diagnostics today as suggested by Brian and this confirmed the LED has failed. I am going to have it repaired by a member on here.

Once these jobs have been completed I am hoping that the car can finally be enjoyed again!

Martin

:wot:
There are so many unknowns. Is it faulty? Were the ports sealed to prevent moisture ingress? Is there any oil in it?
It's a bit unfair to blame the car for your non-genuine head gasket failure and your second-hand air con. compressor Martin! :D
Well, let's say that it suggests a fault in the IPK. I await the results of the diode test after removal. ;)

Simon

So we have identified by substitution of your IPK in another car by Rick, that the LED is functional, here is the wiring for the oil pressure warning lamp circuit

https://the75andztclub.co.uk/forum/a...1&d=1592378106



And a picture of the rear of the IPK to identify the connectors in question......


https://the75andztclub.co.uk/forum/a...1&d=1592379410


And finally the pinout of the connector at the IPK........

https://the75andztclub.co.uk/forum/a...1&d=1592379536

So first things first, do you have continuity from the connector of the oil pressure switch at the engine, up to pin 14 of connector CO230?

Brian :D

Oil pressure warning light
 

Hi Brian thanks for your response. You previously suggested that I run a diagnostic check which I did and which revealed that the LED warning light was not working yet when Rick tested it by substitution it worked. I do not understand why that was.

As I said previously there was power in the white/brown wire and the actual oil pressure switch is new so I believe that the fault lies at the connector which attaches to the oil pressure switch. The connector is sprung but can the actual connector be replaced if so, how do you release the wire and put it in the new connector?

Thanks,
Martin

Martin; if you managed to measure 12v at the WN wire terminal on the connector then the only fault could be that the female terminal needs tightening to make better contact with the male terminal on the pressure switch.
No, the connector won't be available separately and trying to dismantle it won't be easy. They are designed to be secure and tamper proof.

Simon

Look at the diagram of the switch Martin, it is a normally closed pressure switch connected to ground ;)

When the engine is started the signal from the switch goes high, pulling up, this is what extinguishes the lamp.

So Ov on the wire at the IPK engine stopped, 12V when running ;)

Remove the plug from the switch, and earth the wire, does the oil lamp light now illuminate on the IPK?

This will confirm continuity to the IPK of the white/brown wire.

Why was the pressure switch replaced, was this as a response to the oil lamp warning failing to light initially, or for other reasons?

Brian :D

Well folks, all the work now completed and car is running sweetly thank goodness.

New condenser yesterday bit of a pain putting cowl and fan back on but sorted. Regassed today now like a fridge in the car. The air con guy I use is very good not like the usual. He runs Mirageair in North London does nothing but air con including new installations. His prices are reasonable, i.e. recharge £45 including VAT.

The oil pressure warning light problem as expected was a problem with the connector. The Lucar connector eventually came out of the connector which I removed from the oil pressure switch and then just pushed the Lucar connector onto the oil pressure switch and then used a sealant gun to cover the end of the switch with sealant to waterproof it and it is now working fine. In fact Simon you can get the connectors from specialist car electrical suppliers they are only about £2- £3 each but I saw no need at the moment.

The car has now covered about 150 miles and I had to add about 100mls of coolant which I think is normal as there is probably residual air in the system, at least I hope that is the case!

I must say I thought the diagnostics for the instrument cluster would have revealed if any of the LED's of the warning lights had failed but that does not appear to be the case following my experience, be warned!

Hopefully we can now look forward to "Happy motoring...."

Martin

Surely it's not a Lucar connector Martin, like this?

https://images-na.ssl-images-amazon....LebJL._AC_.jpg
You said that these have a sprung wire retainer and I know exactly the type you mean. Please can you provide a link to the supplier you've found? I'd like to keep them on file in case I need one!

Many thanks.

Simon

Simon it is not actually a Lucar connector but it is on the same lines. It is called a JPT connector and see the following link https/www.autoelectricsupplies.co.uk/product/680/category/7-ref051501


Martin

Sorry Martin, I can't make your link work. It just produces a list of Google search results. Then I noticed that the :// was missing after https but even after correcting that I didn't get the page you intended me to see. :shrug:

Simon

They are Tyco-Amp connectors, and the part number for the brown housing is 282189-6, and the contacts 964274-2.

http://www.aoton.cc/download/202054164953283.jpg

https://encrypted-tbn3.gstatic.com/s...6fN8g&usqp=CAc

As you can see, it is a simple case of depressing the two tangs securing the contact into the housing, and gently pulling the cable, and the contact comes out of the housing.

The barbed grommet once the contact is out of the housing, can be released from the crimp and slid up the wire for reuse with the new contact.


Brian :D