Boost leak - intake manifold to head

[godzilla_753]

Hi,

I have an rb25 neo and the intake manifold to head gasket is leaking under boost, confirmed with a boost leak tester.
I took it all apart and the metal gasket looked ok, so I took some Permatex Ultra Grey Rigid and applied to both sides of the gasket and slapped it all together and its still leaking.

Any one have ideas on what to do? I dont mind buying another gasket but it was a huge job taking it apart the first time and Id like to cover all my bases this go around.

I did see some mild scoring to the intake manifold where a stud might have scratched it when I had it apart, could that be the cause of the leak? Also the gasket is metal and only 1 layer.

Would appreciate some suggestions.

Thanks

[Darius]

Did you replace the gasket or just reuse the old one? I wouldn't use a sealant on the surface. Check the intake manifold mating surfaces for flatness. Maybe one or the other is uneven/warped.

I don't think a small scratch would result in a noticeable boost leak.

[godzilla_753]

I reused the same metal gasket unfortunately. Could that be the cause? The gasket looked okay. Also I had the intake manifold welded on extensively, I was also thinking it might be warped.

Going to take it off again. So you recommend checking for flatness and a new gasket? no sealant?

[Yellow4g63]

Get it the flanged shaved down to make sure it is flat. maybe it was warped from the get go?

[Darius]

You have the stock intake manifold, right?

[godzilla_753]

You have the stock intake manifold, right?

Well kinda, I took the stocker apart and modified it to fit rb26 itb's. This involved a bunch of welding. I think Ill need to get it planed....

[Darius]

Yeah if there was too much heat involved while tigging it up, it could have warped the runners slightly. Taking the manifold off is a PITA, but having it milled costs like $35. Not a huge hit to the wallet.

[RRRRB]

Sounds like its warped, aluminum is normally a little more resistant to warping compared to stainless steel ... check it with a straight edge

[godzilla_753]

sounds good. Im gonna tear it apart and check it for flatness, but most likely will get it milled just to be safe.

Thanks guys
Ill report back after I tear it apart