Vr6 Head Gasket

[golfvr6]

I think i might have a head gasket leak on my VR6. Not the usual type of leak, the problem is the vent on my expansion cap keeps leaking. I've tried various caps and a new expansion tank but it still leaks. It leaks more when i boot it. Compression test comes out ok. The question is if the coolant system is being pressurised by a leak in the gasket, then how long can i carry on driving it without big problems? cheers all.

[richandhazel]

I believe you can have your coolant checked to see if there are traces of combustion deposits/gasses in the coolant.

[mk1]

Is there a lot of pressure in the cooling system? I have done lots of head gaskets on vr6 engines and half were for oil leaks and half for exactly your fault. Use only wv gaskets, I also replace the stem seals. Job is not as bad as it looks, unbolt the exhaust manifold from the head and push back, just "crack" the bolt on the rear cam sprocket, time the engine and remove the chain tensioner, then take out the slack bolt and remove the sprocket from the cam, this alows you to take the chain off. The rest is just nuts and bolts. Check the condition of the top chain guide, have had to change some due to plastic breaking off, now thats a bigger job . Hope it is something simple . Steve.

[mk1]

 So you reckon i gotta change the  head gasket then?

Looks like it, some had a small electric coolant pump in the small hoses above the g/box. This is to circulate the coolant around the engine when off to stop heat soak boiling the coolant in the engine. Worth a look?. Steve.

[golfvr6]

You reckon it might be the run on pump? I far as i can see it is working properly. The coolant only leaks out when driving, not if i just let the car run with the bonnet up.

[modulater]

GOLF VR6, have you thought about trying a product called water wetter in the coolant system?  It's supposed to raise the boiling point of the water so it might help.

[golfvr6]

Yep i have thought of it, but i probably want to sort it once and for all really.

[mk1]

Raising the boiling point of the coolant wont change the pressure in the cooling system. Water wetter says it will help transfer the heat from the coolant to the atmosphere better. Driving, higher cylinder pressures, cap venting, I would do the HG before you have a bigger problem. Steve.

[golfvr6]

Cheers for everyones responses. I've put radweld in and everything seems ok for now. Water wetter would probably help but not for long. Probably end up doing the gasket sooner or later....

[golfvr6]

Another question..... i've been told that when there is a head gasket leak that pressurises the coolant system, all the coolant hoses go hard, is this true in all cases?