Hi all. Got my 2010 5.0 serviced end of Feb and new clean MOT. However I do occasionally have an idling problem after long deceleration especially going downhill, and I've got a slow coolant drain (nothing on the drive) and more exhaust vapour than normal on start up. Garage reckons it is the head gasket on the way out. They pressure tested it and it seemed fine but they said keep an eye on it. It's not getting any worse but I still have to top up the coolant by about 1litre every 2-3 weeks.

I've searched for SC head gasket on here but not found a lot, mainly to do with diesels and EGRs. Has anyone experienced similar? Any ideas if the head gasket could be related to this idling issue? Garage has road tested the car for a few days and the idling didn't happen to them - typical. If anyone has had the head gasket replaced on the 5.0, how much did it cost you?

Appreciate any responses

1 litre every 3 weeks is a lot.


maybe it is the egr

Thanks for the reply Andy - do you know of anything I could try/look for that would help narrow it down at all?

There’s not many places coolent can go, in the oil (cream on the cap) in the cylinder (possible excess vapour/water in the exhaust or on the floor. Sounds like it is going into one or more cylinders. Which one is the question. 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

If it was the head gasket i would have thought it would have done it consistently as a crack does not come and go that i am aware of

The coolant leak seems pretty consistent. When it's not used much it drains slower obviously, but it's still draining a little each time I use it.

I'm kind of hoping the rough idling/near stalling is related in some way to this coolant drain. Perhaps if it's the EGR it might be after all.

Problem is, the LR specialist I use said I could book it in for a head gasket job but they won't know for sure what it is until they start taking everything off. Sounds like it could cost me hours in labour even if it's not the gasket and they have to change tact after all. They didn't even mention EGR but perhaps it is that. I do notice slightly more vapour coming out of the left side than the right.

If it was the head then if you stop using it then it should practically stop have you had the sustemmpressiee tested or had it sniff tested to see what’s in the coolant ie any hydro carbons

They pressure tested it and said it was fine, and that there were no leaks in the coolant pipe (hence nothing on the drive). I didn't know about the possibility of it being EGR at the time so didn't ask about that bit

Have they done a sniff test

Sorry forgot to add that I don't know if they did a sniff test. Maybe I should see if a garage can do one for me. The ballpark figure I got for the gasket job was eye watering so I'd like to shop around anyway, so maybe that's an opportunity to get a second opinion.

I would if they have not done a basic sniff test

Normally I would say bypass the EGR coolant pipes and use it for 2 weeks and see if it still drops.

Check the carpets in the front by pushing down on them. Any water?
Windscreen misting up more than usual ?

Yeah you don't want to spend all that money on HG without more proof!

I’ve been away a while flirting with other motors but now back with a 2013 Black edition - love it.

I have just had your problem with SWMBO’s BMW, it was the EGR cooler. Loss of coolant but no real visible evidence. I thought it was the head gasket but no sludge or loss of power. Luckily we had warranty, but whatever, it needs fixing.

Ah interesting. I double checked under the oil cap for sludge tonight and there wasn't any, also no loss of power. Was the EGR cooler a big job?

This sounds like a classic head gasket fault, but in these modern times, a water cooled EGR might be the source of the problem. If you have increased steam from one bank of cylinders, then the water is going there, not into the sump.

It sounds like it needs monitoring for a bit longer before committing to a big spend.