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Old 14th August 2019, 18:00   #11
SD1too
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Quote:
Originally Posted by Matt70 View Post
... the mechanic diagnosed HGF it's easy to proove using a special instrument ...
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 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
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Old 15th August 2019, 20:56   #12
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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
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Old 16th August 2019, 07:59   #13
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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.


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.

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Old 23rd September 2019, 11:25   #14
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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
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Old 23rd September 2019, 12:05   #15
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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
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Old 23rd September 2019, 12:55   #16
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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
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Old 23rd September 2019, 14:17   #17
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Martin,

Have you fixed the absent low speed fan?
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Old 23rd September 2019, 15:12   #18
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Martin, Have you fixed the absent low speed fan?
Yes he has (Post no. 7 Ken).

Simon
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Old 23rd September 2019, 16:54   #19
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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
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Old 23rd September 2019, 18:05   #20
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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.
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