Downpipe flange leak

[Steve 940]

Hi Salvador P

As I'm still trying to build up the courage to sort this, I done a bit of digging around on the forum, and there seemed to be a general consensus that the exhaust manifolds are succeptible to cracking as well!!!

I bought all new studs etc. as a belt and braces approach, as I feared taking everything apart and then finding one or more of the studs shearing off, leaving me in a bit of a pickle...... oil supply pipe to Turbo oil sealing ring was also highlighted as an almost 'must' replace. I use mine as a daily driver so can't really afford to be off the road waiting for parts.

I found using my workshop vacuum on blow stuck up the exhaust tail, allowed me to use trigger spray with soapy water on joints to find leaks, however really difficult to get water onto underside of manifold to see if leaking there also. Trying to do with engine running I found the water evaporated so quickly and the turbo gets hot rather quickly to be poking around with your hands.

Hope you get sorted, and any suggestions or findings most welcome.
Cheers
Steve

[TonyS9]

Originally Posted by Rversteeg

Although normally a gasket is not used, a gasket used for eg the 850 can be fitted. OEM art. no. 8642450

Is that not between the exhaust manifold and the turbo? The OP was about the downpipe join.

[TonyS9]

Originally Posted by SalvadorP

My 1997 940 lpt has a leak at the flange between the turbo and downpipe.
I am yet to disassemble the flange so I'm not sure if there is a gasket there or not. Can someone help me clarify that?

I'm planing on using putty to seal it.

It should seal without putty, just make sure all 3 bolts are tight and the flange is not cracked. The studs have a habit of coming out of the turbo.

[SalvadorP]

Turns out the gasket between turbo and manifold is also leaking.

[SalvadorP]

Originally Posted by TonyS9

Is that not between the exhaust manifold and the turbo? The OP was about the downpipe join.

Oh, that makes more sense. Because the gasket has 4 holes. And the flange has 3 bolts.

Anyway, in my car there is indeed a gasket between the turbo and the manifold, maybe one of these mentioned above, and it's leaking. I can't find that gasket locally. I'm considering just covering the gap with putty.

[Steve 940]

Hi Salvador P

Sorry to hear your source of the leak is also between tubomanifold.

If you scroll through the earlier thread I suggested, you should hopefully see a post from the fount of all knowledge, Laird Scooby, wonderfully helpful, and has pointed me away from potential disasters

I had asked if possible to repair using exhaust putty, but he quite correctly pointed out that if a bit of the hardened paste comes away, it then goes straight into your Turbo, not a great outcome I would assume. Also it can damage the cat apparently.

He did suggest if mating surfaces are not absolutely flat, then possible to use perhaps 850 gasket if you can find one, or a sheet of 1mm copper with holes.

Cheers
Steve

[SalvadorP]

Thank.s I've read the whole thread. Issue is I'm about to travel back to another country and I have to fix it right away. No time to wait for parts to come from skandix and whatnot. And I can't find the gasket locally. We are doing the work at my friend's shop. I'll talk to him if making a gasket out of copper is an option. I don't know where to buy the copper sheet. He might know.

[Steve 940]

Hi

Apologies, I've just seen your location, and sorry to hear you need such an urgent fix.

If you need it urgently, I would be very wary about pulling this apart, as it seems it can be quite common to get a stud shear. Might be worth considering postponing the repair until you are able to do the work with various parts in hand so that you won't be off the road too long.

Obviously depends on how bad the leak is, mines been leaking since Christmas time, and not really got any worse.

Best of luck,Cheers
Steve

[SalvadorP]

We've worked on it this afternoon. We applied exhaust putty (says it's good up to 1500ºc) on the flange. Couldn't find no cracks at all.

Afterwards the car was still leaking smoke, but mechanic thought it was from the wd40 burning off. After a while it stopped.
But I am not convinced it was from the DW40. I believe by heating up the metal expanded and stopped leaking. I believe it is leaking from the bottom between turbo and manifold. Tomorrow with the car cold and free of wd40 I will know for sure.

Can't do anything now though. Don't have the 850 gasket nor time to do it. The leak seems kinda bad, but seems to stop once the car is hot.

Yeah, I know those studs are prone to cracking. The ones that connect the turbo to the manifold also look like a bitch to come out. There is no space for the wrench. My nightmare would be to have a stud break off in the turbo or even wrose, the engine and have to drill it out...

[Steve 940]

Glad you've been able to get a look at this, and yes, mine quietens down when the engine is hot, so as you say the expansion seals up the leaks a bit.

As soon as you've got a few days to pull it apart and do the repair fully, then hopefully that will be a permanent fix.

I just need to do the same job, and build up some courage to dive in, plus getting some days free to actually do the job.

Hope your upcoming journey is uneventful.

Cheers
Steve