Elusive Gti6 Exhaust Blow...

[macaroni 17 1 Cars]

Hi,

my gti6 engined-205 has a very elusive exhaust blow.

 

I've had the entire system off, including Maniflow manifold, and replaced the gaskets and sealed the joints, but still it persists.

 

It sounds like it is coming from the engine bay side of things and the manifold doesn't appear to be cracked either.

 

My feeling is that is might be coming from the head gasket?

Is this possible without any other symptoms of a blown gasket?

 

Antony

[jackherer 543]

Get someone to block the tailpipe with a rag while you watch for leaks.

[petert 586]

Get a small amount of brake fluid (<100mL) and suck it up with a vacuum tube. White smoke will pour out of any crack. It happens very fast, so get some help.

[Miles 331 1 Cars]

Is it the std road spec Maniflow manifold? The flanges are worth checking to see if they are flat and always use loads of exhaust paste with them as they generally sit close to the bulk head and sit low under the car which and knocks can disturb them.

[macaroni 17 1 Cars]

Thanks for your input chaps.

 

I've done the rag over tailpipe diagnostic check and it is definitely coming out near the manifold/head, just can't see where.

 

Can you explain more about that trick Peter? Where do I put the brake fluid?

 

That sounds quite likely Miles, and I suspect with manifold is the std one as you suggest.

The exhaust has had a few knocks due it hanging quite low.

Are you suggesting the manifold face against the head isn't quite flat? I guess the only solution to that is to plane it flat, which means engine out to fully remove the manifold.

 

Antony

[allye 530 3 Cars]

my punt is warped manifold mating face.

[petert 586]

 

Can you explain more about that trick Peter? Where do I put the brake fluid?

 

Any vacuum tube that enters the inlet manifold can be used. eg disconnect the fuel pressure regulator vacuum, put the hose into a cup with a small amount of brake fluid. As soon as you start the engine, the entire amount of brake fluid will get sucked into the inlet manifold. You won't have time to come around the front and check. Thus I said you'll need help. Definitely <100mL. It creates an unbelievable amount of white, thick, harmless smoke that will come out of any exhaust leak.