Motor Valley Oil Leak

[n0n0_1963]

I have an oil leak on the top of the back of the motor ( valley ) and try to find what could be wrong. The motor is a "c" code with a "j" manifold.The leak start to happen after I install a banks turbo. The first thing I did is changing the rear seal, this one was made out of rope and was completely worn out. It Still Leaking. I replace the gasket for the vacuum pump, this one was in a bad shape. It Still Leaking. I change the intake gasket and seal them with Permatex. It still leaking. I spray some cleaner on the motor and I can see that the leak is coming from the rear of the motor's valley, but I can't see where the leak come from. I run out of idea what could be wrong :(

[catmandoo]

this may sound stupid but what about the oil pressure switch.

[britannic]

Some other places to check:

The inj. pump gasket to timing case can spring a leak after adjustment.

If it's a small amount of oil, it can also be coming from the seal between the intake manifold and the Bank's pressure chamber.

A fuel leak from the inj. pump can masquerade as oil as it picks up deposits on it's way down the valley and into the flywheel dust cover and out of the drain hole underneath.

A faulty CDR valve will also allow too much pressure to build up in the crankcase and cause even a good rear seal to leak - I just found this out on my own engine.

[n0n0_1963]

Thanks for the fast replies and the good ideas, for the oil sensor I read that they have tendancy to crack, but the dripping come from both side and the coupling is dry. The cdr valve was replace and the vacuum take at the dipstick is in the spec. require by the manual. Sinca all the valley is oily, I will check the seal on the intake manifold, it is new but never know. For the leak on the inj. pump to the timing case i'm very interested on this case, the cover and the holding stud of the pump was remove to set up the fuel pump at the installation of the banks turbo, who is very impressive by the way,Do you have any more details, and did this happen to you?

[catmandoo]

you said you replaced the intake gasket and used permetex.did you by chance use it on the end seals if so you can get what is i think called a hydraulic lock whereas when you tightened it down the sealer ends up pushing the seal out of the way . this is why they say to put them in dry with only a little sealer at the corners.

[NH2112]

There are no end seals for a 6.2 intake manifold like you'd find on a 350. You only have the manifold-to-head gaskets.

I'm thinking it could be the CDR tubes - if one of them is cracked, the rubber elbow is deteriorated, or even if the fitting in the side of the intake or the intake itself is cracked, any oil in the tube will eventually end up in the valley. I'd recommend pressure-washing it really well then getting a small bottle of UV dye to put in the oil, and a UV filter for your flashlight (blue lenses will cause the dye to fluoresce somewhat too.) Run the engine for a while, look for yellow streaks or spots, and follow them uphill to the source!

[n0n0_1963]

Okay, I spend some time to look again for this *&^%%#&$^# leak, I put a rag in the motor's valley and this one stay clean, I not too shure that the leak is coming from the top anymore. I change the rear seal not a long time ago and I install it with a quarter inch off set. I start to think that this is the problem. I had a blew rope and replace it by a viton one. Any off you experience this before. Any Idea how to check it, I don't want to do this messy job again if I'm wrong. It's so hard to see exactly what's happening over there.