3126b exhaust manifold oil leak

[MatthewWBailey]

I'm developing an exhaust manifold oil leak coming from the aft cylinder. This has begun manifesting since I changed the exhaust route and added the heat shields and upgraded to the 330hp Tune and Amsoil synthetic 15w-40.

 

[Ronmar]

Is it coming out of the manifold port? either a crack, or perhap a valve guide seal?

 

[Keith Knight]

When I replaced the oil cooler gasket a few months ago I noticed my rear exhaust manifold had some soot around it after further inspection the back bolt or nut was loose. Tightened it and no more soot.
is yours soot that has gotten wet and give it that look?

 

[MatthewWBailey]

Is it coming out of the manifold port? either a crack, or perhap a valve guide seal?

It's concentrated around the first cylinder

When I replaced the oil cooler gasket a few months ago I noticed my rear exhaust manifold had some soot around it after further inspection the back bolt or nut was loose. Tightened it and no more soot.
is yours soot that has gotten wet and give it that look?

it has an oily consistency but I'm not sure.

 

[GeneralDisorder]

Check the plate covering the waste gate port/linkage on the turbo. The last one I did needed a whole new turbo because the cast iron exhaust housing was warped and it would not seal not matter what we did to it. Only $2300 for another turbo from CAT.

Could also easily be rust-jacking of the manifold bolts or a warped manifold or the bolts are broken just being held by the rust.

I think it was already deleted by the 3126 but CAT did change from a single piece to a three-piece manifold somewhere along the line due to the long single piece castings warping over time.

 

[MatthewWBailey]

Check the plate covering the waste gate port/linkage on the turbo. The last one I did needed a whole new turbo because the cast iron exhaust housing was warped and it would not seal not matter what we did to it. Only $2300 for another turbo from CAT.

Could also easily be rust-jacking of the manifold bolts or a warped manifold or the bolts are broken just being held by the rust.

I think it was already deleted by the 3126 but CAT did change from a single piece to a three-piece manifold somewhere along the line due to the long single piece castings warping over time.

Here is what the manifold looks like 2500 miles ago at the overhaul..