oil leak

[Ethan]

Anyone have a oil leak on there 91? Has anyone heard of a head gasket leaking or blowing out on the driver side back where the oil drain back hole is?Or anyone had the oil galley plug under the driver side head leak. Already replaced intake gasket,valve cover gaskets,both oil sending units also took all fittings out and pipe taped them.It is a pressure leak too much oil coming out.ad I,m just about the point of ordering a high torque 383 from GM.

 

[Alan86]

I had an oil leak roughly in the same area that was difficult to locate. What I found.... I removed the oil filter and found a large nut that was working loose (I thing it was about 1 inch in size). This nut held the oil filter to the block and had the coolant lines attached to it. After tightening it, the oil leak stopped.
Perhaps maybe??????

Alan

 

[rrubel]

Sounds like your oil cooler was coming loose - there's also a gasket at the top of this that can leak. The cooler is optional, though, so not everyone has it.
[RICHR]

 

[Ethan]

Well here we go again pulling the intake off again seems the back seal (silicone) sorry if spelled wrong dont have Pam Andersons phone # to get correct spelling.Any how back intake seal is leaking again .I dont get it , it has squeezed out at least half an inch but still leaking.It,s a Elderbrock big mouth intake maybe it was not molded correctly anyone else use this intake on their L98 ?

 

[cntrhub]

Sometimes, an over filled crankcase increases oil pressure inside the engine block. Have you checked the oil pressure? This check is done near the oil filter housing. There is a fitting that you simply unscrew, screw in a generic oil pressure hose, and read the PSI at idle. The higher the rpm, the higher the pressure. This will eventually "blow off" to a specific number (depending on health of bearings, ect.). If the pressure keep rising, and does not stay steady when increasing rpm, you have a stuck bleed off valve. This might be your problem?
Now for the manifold. You might have a poor fitting intake manifold. The leak you think might be coming from the back of the engine, just might be the oil leaking out the back of the intake manifold. Install the manifold "dry" in place. Use 4 manifold bolts and tighten the 4 corners. Do not use any silicone...this is a gap test you are going after. Take a mirror and inspect the gap between the surface of the engine block and manifold. If the gap is anything larger than 3/8" of an inch, you may have to machine the maniflold and get it to drop a few 1/16th of an inch.
Does the ball in the PCV rattle? This also may increase crankcase pressure.
The best silicone to use for the intake manifold is sold at GM. Tell parts you are installing the intake manifold and he will hand you a tube of the good stuff.

 

[69MyWay]

The oil cooler is the killer. The way it mounts to the block between the oil filter and block it is prone to leak. I have dealt with it before.

Go to G.M. and get the new gasket/o-ring seal kit for the cooler. Pull it down, clean it up, reseal it, and see if the leak does not go away for a very long time.

 

[Ethan]

oil leak fixed (well so far)

Twas the intake again well cleaned it off good with carb cleaner squeezed some (Pam Anderson enlargment goop) silicone in and whalla that with a new pcv I think did it for a while. Well anyhow that Lt4 hot kit really makes the ole L98 scream. Adjusted the 700r4 to shift out of 1st at 6,000 thats at 65mph (2.59) gears sucks I know but this thing pulls hard! Just need some 3.45 or 3.54 gears , shifts into 3rd at 85mph! Man I need gears! Any you guys with the 1.6 roller aluminum rockers(question) Are these noisy or what sounds like a solid cam in this thing not a roller cam? Re- adjusted valves helped some I guess between the 30lbs. Motorsports injectors and these rockers there will be some noise. These injectors are loud .