Kapok6
15+ Year Contributor
- 1,392
- 267
- Aug 10, 2004
-
Fort Worth,
Texas
Alright, I have been trying forever to figure this boost leak out and have been unsuccessful thus far. Here are the facts.
Boost leak test reveals boost leaks coming from the dipstick and the valve cover. (see vid)
Dsm boost leak test - YouTube
Initial thought...boost leaking through rings pressurizing the crank case and thus casing the head to be pressurized as well as that pressure would also come up through the oil ports into the VC area.
I did a compression test (built motor) and it's 160-170 across. That's not adding oil into the cylinders, that's just pulling the spark plugs and testing.
2nd theory, my valve seals have to be leaking then, allowing pressure to go from the head/VC area through the oil ports into the crank case therefore pressurizing the whole system. So I pull the VC to see if the seals are leaking.
2nd vid
Dsm boost leak test 2 - YouTube
I can not detect any of the seals leaking. But pressure is still coming up from crank! If the seals were leaking, with the VC off, the crank case shouldn't see any pressure. The pressure would come through the valve seals and into the atmosphere since there is no VC to hold the pressure in.
You can also hear what sounds like oil bubbling through oil. So now we are back to, " the leak has to be originating though the crankcase first then into the head. Bad turbo seals allowing oil into the oil feed/return? I have had these results with 3 different turbos! Rebuilt MHI Evo 3, and two FP 3065's.
I am stumped. I have no idea where this leak is originating!
Any other thoughts?
-Ryan
Boost leak test reveals boost leaks coming from the dipstick and the valve cover. (see vid)
Dsm boost leak test - YouTube
Initial thought...boost leaking through rings pressurizing the crank case and thus casing the head to be pressurized as well as that pressure would also come up through the oil ports into the VC area.
I did a compression test (built motor) and it's 160-170 across. That's not adding oil into the cylinders, that's just pulling the spark plugs and testing.
2nd theory, my valve seals have to be leaking then, allowing pressure to go from the head/VC area through the oil ports into the crank case therefore pressurizing the whole system. So I pull the VC to see if the seals are leaking.
2nd vid
Dsm boost leak test 2 - YouTube
I can not detect any of the seals leaking. But pressure is still coming up from crank! If the seals were leaking, with the VC off, the crank case shouldn't see any pressure. The pressure would come through the valve seals and into the atmosphere since there is no VC to hold the pressure in.
You can also hear what sounds like oil bubbling through oil. So now we are back to, " the leak has to be originating though the crankcase first then into the head. Bad turbo seals allowing oil into the oil feed/return? I have had these results with 3 different turbos! Rebuilt MHI Evo 3, and two FP 3065's.
I am stumped. I have no idea where this leak is originating!
Any other thoughts?
-Ryan