Oil Leak question!!

[Mean Green]

Okay, so i have had an oil leak in my 94' for over a year now. And quite frankly it's driving me crazy lol I have a rough idea of where it's coming from. I put it up on the hoist, and completely degreased the bottom of the motor, the entire bellhousing, and the sides of the motor as well. The leak is coming from the top of the motor, somewheres towards the center (as oil runs down both sides of the bellhousing, and ends up dripping on the Y-Pipe). SO my theory is it's either the rear of the intake gasket, the distributer o-ring (unlikely), and/or the oil pressure switch. I'd like to know what you guys think, ANY suggestions on diagnosing this, and also what is prone to leaking back there on the GMT400's?

Specs on the truck: 1994 GMC K2500, 123,*** miles, 350 TBI, 4L60E auto

Thank you in advanced guys!!

 

[Aloicious]

I would vote the oil pressure switch adapter elbow. if the TBI uses the same elbow adapter as the L31, its a known leak point. you should be able to remove it, clean it up, and put it back with a little sealant and be good.

 

[Mean Green]

I would vote the oil pressure switch adapter elbow. if the TBI uses the same elbow adapter as the L31, its a known leak point. you should be able to remove it, clean it up, and put it back with a little sealant and be good.

Okay, i think i'll pull that out tomorrow and check it out! It's hard to get back there to really see where it's coming from. I'd really REALLY like to get this fixed!!!

 

[Aloicious]

yeah its a pain getting to stuff back there, but thats what I'd vote on.

 

[Mean Green]

Alright, i just pulled up the diagram. It appears, that the 94 down TBI engines uses the 90* elbow. Here's the diagram anyhow, the elbow is #103.

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[Aloicious]

my '96 is a 90* elbow too. perhaps its setup a little different or something. unfortunately TBI's aren't overly known territory for me.

 

[miles5241]

yea i've had the same leak for a year now to but only leaks when the motors running. and i've done the rear main, oil sending unit, and intake... so if you figure anything else different you should let me know before i decide to say screw it and buy a new motor

 

[Sully]

sbc = oil will leak

 

[dirtridinz71]

You should be able to use a swivel mirror from the top of the motor and get a much better idea where it is leaking. I did intake gaskets once and didnt get enough silicon in the corners of the back valley on the block. It took a while but it developed a bad oil leak from one corner.

 

[Mean Green]

You should be able to use a swivel mirror from the top of the motor and get a much better idea where it is leaking. I did intake gaskets once and didnt get enough silicon in the corners of the back valley on the block. It took a while but it developed a bad oil leak from one corner.

I know it's not the rear main, as it's coming from the top of the motor. I took the inspection scope back there, and still couldn't narrow the leak down to a specific point. An intake gasket is a possibility for me, because of some symptoms the truck's been having the last week or so, but that's another topic. Hopefully later on today or tomorrow, i'll get a chance to pull out the Oil Pressure adapter and check that out. HOPEFULLY that's the cause of the damn leak!