I would recommend cleaning it off, but not till you are ready to install it. If it is just some type of oil brake clean should do the job, but if it is meant to be a permanent clear coat or something you might need a die grinder and a cleaning disc that won't mar up the metal too much.

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Its def not oil. Its a hard coat of some type. Hopefully my dremel will suffice.

I can't think of a single dremel attachment that won't mess that mating surface up, and I do own a dremel and have a 249 pc attachment set for it. If you don't have a die grinder with an appropriate wheel, then use sandpaper and a block of wood or something flat, or just leave it on there. But don't take a sanding drum or grinding stone or something to it...

Using a new gasket should eliminate any possible leaks. I'd leave it on and use a gasket. Why don't you call the people that rebuilt it for you and put the shtuff on there?

Xploitn said:

Using a new gasket should eliminate any possible leaks. I'd leave it on and use a gasket. Why don't you call the people that rebuilt it for you and put the shtuff on there?

Click to expand...

I agree. Call the vendor and ask them what you should do. If you go grinding the stuff off, you could easily mess up the surface so that it doesn't seal to the O2 housing.

I would leave it alone an install the turbo, the gasket should seal just fine.

No harm in using some ultra copper RTV in conjunction with that gasket...
Our typical setups hit max 1600ish F exhaust temps but the housing itself won't get that hot so the ultra copper does okay.
Gasket Makers : Permatex® Ultra Copper® Maximum Temperature RTV Silicone Gasket Maker

Thanks guys this is good stuff. Ive worked on my stuff a little but this project is way more than im used to.

So I called michigan turbo and they said it would be fine to leave it on. Its called "spray cast." Apparently they bake it on and its high heat resistent. Thanks again for all the input.

I use the same product, but I'm not so lazy/unprofessional as to leave it on flanges. That would make me question what other corners were cut.