Overheated 2.5 V6 and failed rad hose

[StephenEssex]

Hello All, today for the first time my 2000/W reg 2.5 V6 Auto has let me down, it was running sweet as always but I stopped and parked up and got out the car and noticed coolant running along the road so popped the bonnet up and coolant was spraying out the hose beside the engine with the small bleed screw on the top (main engine to rad hose). Called the RAC who turned up and obviously got the usual HGF symptoms and this car looks finished type comments... he said the coolant looked oily but doesn't OAT have an oily film on the top? there was some small bits of sludge that came out and the rad wasn't getting warm, the top hose had some of the OAT'y coloured sludge build up in it too. He towed me home.

Oil is clean, car has not been using water (maybe the occasional cup full every so often) no smoke or steam on start up.

The coolant was flushed and replaced on 68,000 miles just over 3 years ago (now on 75,000 miles)

I think the coolant was due another flush and replace, I know the heater matrix is silted up as the heaters don't work. There was some air in the system apparently and in the end the diagnosis from RAC was a poor flow of coolant causing it to boil up and force its way out this hose (not the expansion cap)

Thoughts please chaps?

Kind Regards
Stephen

[slovcan]

Originally Posted by StephenEssex

Hello All, today for the first time my 2000/W reg 2.5 V6 Auto has let me down, it was running sweet as always but I stopped and parked up and got out the car and noticed coolant running along the road so popped the bonnet up and coolant was spraying out the hose beside the engine with the small bleed screw on the top (main engine to rad hose). Called the RAC who turned up and obviously got the usual HGF symptoms and this car looks finished type comments... he said the coolant looked oily but doesn't OAT have an oily film on the top? there was some small bits of sludge that came out and the rad wasn't getting warm, the top hose had some of the OAT'y coloured sludge build up in it too. He towed me home.

Oil is clean, car has not been using water (maybe the occasional cup full every so often) no smoke or steam on start up.

The coolant was flushed and replaced on 68,000 miles just over 3 years ago (now on 75,000 miles)

I think the coolant was due another flush and replace, I know the heater matrix is silted up as the heaters don't work. There was some air in the system apparently and in the end the diagnosis from RAC was a poor flow of coolant causing it to boil up and force its way out this hose (not the expansion cap)

Thoughts please chaps?

Kind Regards
Stephen

Hi Stephen,

My thought is that your head gaskets are fine and you need a new rad hose. You have low mileage, it was maintained and the coolant was flushed earlier than a lot of cars get that done. I do find it strange that the heater core would be silted up considering the cooling system was maintained.

Anyway, new hose, check the remaining coolant hoses for signs of seeping and going soft with age, replace any that are suspect and happy motoring.

Cheers,
Glenn

[Mgaz]

Any pics of where exactly it is coming put from?

Maybe get a new hose on there, perhaps even a proper jubilee clip and fill the water back up and see if she leaks again?

[SD1too]

Originally Posted by StephenEssex

Thoughts please chaps?

Here are mine!

... coolant was spraying out the hose beside the engine with the small bleed screw on the top (main engine to rad hose).

First of all, just to clarify, that hose is the return from the radiator/oil cooler to the thermostat.

Called the RAC ... got the usual HGF symptoms and this car looks finished type comments... he said the coolant looked oily ..

His opinion on the coolant condition appears to be an attempt to justify his hasty, ill considered and uninformed diagnosis. Ignore it.

... there was some small bits of sludge that came out ... the top hose had some of the OAT'y coloured sludge build up in it too.

You should not have sludge, particularly after flushing the cooling system. Did you do this yourself?

... and the rad wasn't getting warm ...

Can you expand on this please Stephen as it sounds crucial to a diagnosis. Which surfaces did you test for temperature, presumably immediately after the coolant loss? When you lifted the bonnet was there a lot of steam?

I know the heater matrix is silted up as the heaters don't work. There was some air in the system apparently ..

Hmmm, yes. A non-functioning heater matrix can result from a poorly bled cooling system, not just a blockage. When the system was last drained, was it refilled and bled by following MG Rover's procedure exactly? Was the expansion tank lifted? Was the bleed screw refitted before starting the engine? If the method isn't followed properly, air can remain.

...and in the end the diagnosis from RAC was a poor flow of coolant causing it to boil up and force its way out this hose (not the expansion cap)

I don't find that very convincing. What caused the poor flow of coolant (the heater matrix would not be a factor)? If it boiled, your temperature gauge would have flown up to maximum, the fan would be roaring and the expansion tank cap would have vented the coolant. Can you actually see a rip in the hose? If not, was the bleed screw loose?

Can you come back to us please Stephen so that we can devise a plan of action, starting with confirmation from an inspection that the suspected hose was definitely the source of the coolant loss.

Cheers,

Simon

[StephenEssex]

Hi Chaps, thanks for the replies.

The temp gauge did not move above half way, the high speed fan did not kick in and there was no steam. The hose looks to have failed and giving off a steady squirt of OAT from just behind the bleed screw.

Here is a photo I took, the coolant is squirting out from that seal just behind the screw.

Culprit by steve wilson, on Flickr

No I didn't flush the system myself it was done by the garage that did the belts in Nov 2016 and 68,000 miles. (now 75,000)

It was the RAC man that said the rad wasn't getting warm but it did start to get warm once he back filled it.

He did comment that the engine didn't seem that hot. he could put his fingers in the coolant and hold the pipes. He confirmed the thermostat was opening and the water was getting pumped when he revved it. When he removed the top hose he showed me the NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD-NAUGHTY WORD- in there, not completely blocked by any stretch but certainly OAT'y sludgy deposits.

Once the car got back up the temp (RAC turned up after 1 hour so had partly cooled down) the coolant started spraying from that above hose again.

With regards to the rad temp I didn't touch anything after the initial breakdown, left the bonnet up and let it cool whilst waiting for the RAC.

The RAC guy said it has 'cooked itself' before he had his van door shut so he was slightly hasty once he saw a coolant leak from a 75. I was fully expecting that reaction though.

[Sheraton]

looks to be Oil mixed with the Coolant to me.


"car has not been using water (maybe the occasional cup full every so often)" - surely then the Car HAS been losing Coolant.


Paul.

[StephenEssex]

Hi Sheraton, yes that's right the occasional cup full of water to bring it back to the mark but not enough to give me a HGF scare. The oil is clean.

I suspect the oil cooler could be leaking? That might have to be bypassed for now if it is.

[SD1too]

Thanks very much for a very helpful reply Steve.

So there's no evidence of any overheating, just loss from the bleed screw area and very unhealthy looking coolant. OAT solution normally has a pale pink appearance, not luminous orange gloop as you appear to have! I wonder if the garage you used put an additive into the coolant and didn't bleed the system properly. That might account for the sludge and the non-functioning heater.

So I'd say Steve, don't use that garage again, just to be sure.
After checking that it's not something simple like the bleed screw loose or cross threaded, order a replacement hose from Rimmer Brothers.
Find someone to fit it and use a flushing agent to try to remove the orange sludge. MGJohn drives his cars for a short time with the flushing agent still in the coolant and reports good results.
After draining, refill with 50% OAT solution making sure that your new garage follows MG Rover's procedure which is here.
Consider temporarily by-passing the oil cooler if you suspect that it is reponsible for the sludge. I'm not sure that the colour of yours is the normal result of oil and coolant mixing though.
Now see what happens.

By the way, don't be too concerned about previously having occasionally to add a cup full of water. I had to do that until I (1) renewed the expansion tank cap seals and (2) positioned the straight pipe clips correctly. Furthermore, if your oil cooler is leaking, that is another possible explanation.

Simon

[StephenEssex]

Thank you Simon, the garage have been excellent and are very highly regarded in MG Rover circles, I won't name them but they did a lot of work on the car early in my ownership and done an excellent job of replacing the belts so I am inclined to show them another good hand, very knowledgeable ex MG Rover mech. I will get the oil cooler looked at as the coolant did have a oily residue on the road, difficult to tell from this photo I took soon after I opened the bonnet, as you can see no steam and and temp gauge never once budged past 9 o clock.

Broken Rover 75 by steve wilson, on Flickr

[Sheraton]

Originally Posted by StephenEssex

Thank you Simon, the garage have been excellent and are very highly regarded in MG Rover circles, I won't name them but they did a lot of work on the car early in my ownership and done an excellent job of replacing the belts so I am inclined to show them another good hand, very knowledgeable ex MG Rover mech. I will get the oil cooler looked at as the coolant did have a oily residue on the road, difficult to tell from this photo I took soon after I opened the bonnet, as you can see no steam and and temp gauge never once budged past 9 o clock.

Broken Rover 75 by steve wilson, on Flickr

that's a Nice Car you have


a problem with the Oil Cooler sounds like a Good call - and hopefully an easy fix (?)


Paul.