Exhaust paste/sealant on turbo diesel manifold (1 Viewer)

[AirheadNut]

My engine has blown through two exhaust manifold gaskets back to back, I am beginning to think either the manifold or the cylinder head have a bit of warping or wear that is causing the MLS gasket to not seal properly. Long term I am replacing the manifold and turbo and getting the head rebuilt, but in the meantime would a high temp exhaust paste work to help seal up the gasket? I've never used something like that, so don't know what to expect of it. For reference this is on a VW TDI engine: aluminum head with cast iron turbo manifold.

 

[Eurasiaoverland]

If you're in the market for a bodge-fix, I'd probably cut pieces off an old MLS gasket and use them to shim the individual ports to get a seal.

 

[aztoyman]

The only time I've used a paste product was in the slip joints of a multi section exhaust manifold. And it was spec'd to be used there. I don't know if a paste would help you in your situation. I agree with @Eurasiaoverland idea above as a better possible solution. It might end up being one of those temporary fixes that last forever.

 

[Themcfarland]

The previous owner used the paste type sealant in my 2 piece exhaust manifold when they tried to remove it and broke a stud off .
They punted instead of replacing the head or going further they used the putty and some clamps to seal it up it does hold , but looks like hammered dog s*** it will be a one way door if you use it never be able to use what you put it on again after removing from service

 

[AirheadNut]

Taking a closer look at the head this evening and I was able to get a decent photo of the #1 exhaust port, this is the one that I suspect to be leaking due to a bit of wear around the port. The first gasket failure was due to the manifold nuts loosening on the #1 port, causing the gasket to vibrate like a reed under engine load and wearing a slight groove into the head. It isn't super deep, but I can definitely feel it with the tip of my finger and my finger nail just catches.

 

[aztoyman]

Do you have any more material options for this gasket? Something that may seal against a less than perfect surface compared to the MLS?

 

[AirheadNut]

Do you have any more material options for this gasket? Something that may seal against a less than perfect surface compared to the MLS?

Looks like there are graphite composite gaskets available that would fit, seems like that would probably seal better on a damaged surface.

 

[Dougal]

Is the manifold flat with a straight-edge check? If not get a machine shop to face it. MLS gaskets are used because they're the only thing that lasts and allows the movement necessary.