Corrado VR6 Head Gasket

[Conker]

Hi All,

Thought I would get a faster response to this back on the good ol' GTI forum...   

After a lot of checking/testing, plus reading old posts, I think my VR6 head gasket has gone. It would be great if you peeps could agree or disagree before I take the head off - heres the situation:

1. The car has been a little down on power recently.

2. While overtaking on full throttle last week the main coolant hose to the head blew apart [spectacularly!], which suggests either it was a worn hose or that the coolant system is pressurising.

3. Since refilling the coolant, there are now small specks of oil in the coolant. But they don’t seem to be growing in number.

4. The exhaust fumes have quite a sweet smell to them now.

5. Compression test shows all cylinders with between 190 and 200 psi, except for cylinder no.5, which is around 160 psi (which is still a respectable result).

6. The engine uses very, very little oil or water. Nor does it overheat. No mayo visible, no steam out the exhaust.


Based on the compression test result for cylinder five, plus the coolant hose explosion, I’m thinking it’s head gasket.  Am I missing something?



Cheers,
Dave

[AudiA8Quattro]

Are you getting any coolant come out of the header tank cap, what happens when the system over-pressurises, its always a bit wet around the tank.

[Conker]

Are you getting any coolant come out of the header tank cap, what happens when the system over-pressurises, its always a bit wet around the tank.

Nope, no coolant has been seen coming out the header tank, but then I haven't been massively heating the engine up since the hose blew as I've been trying to avoid a face full of boiling coolant. 

I've had it up to 85 degrees oil temp, and by that point the hoses felt quite hard, plus there was a large hiss when undoing the header cap. Lots of bubbles are visible in the header tank, but this could be air-locked air finding its way out.

 

[AudiA8Quattro]

Get the system pressure tested, or get the system sniffed for exhaust gasses.

[Conker]

I've decided I'm going to take the head off.

B#llocks.

[Wayne]

I've decided I'm going to take the head off.

B#llocks.

Would it not be worth getting it tested 1st.

[Horney]

Don't these engines suffer from ring and bore wear on Number 5?

Nick

[cняis]

Don't these engines suffer from ring and bore wear on Number 5?

Nick

yes

[Conker]

Technically, theres only a full leak test left to do, and I can't be bothered to pay to get it done - the money would pay for some of the parts, and theres definitely issues that need sorting.

I could have a sniffer test done, but it would more than likely fail anyway as theres definitely oil and carbon in the coolant (albeit a tiny amount) which must confuse the result.   

I've had a knowledgable mate look at it and he reckons its worth taking the head off based on the signs. If the HG's not "gone" as such, its probably about to, and its cheaper to resolve now without a potential warped head to deal with. Anyway, I've bought a new runabout to play with now for a few weeks while I fix it.   

As for piston and rings, fingers are crossed on that one, although all the plugs are clean, dry, and a nice colour so that helps me feel better.

Cheers all,
Dave

[AudiA8Quattro]

The sniffer test is a the way to go, if it fails then the gasket/head is leaking.