Mystery oil leak

['89/'92Chevy/GMC]

As a few of you know I have my '89 stripped down and am in the process of a body transplant.

When I pulled the cab off I found that there was a bunch of oil mess all over the back of the engine and transmission, I figured it was from the intake gasket leaking. So I cleaned up the trans and back of the engine some and plan to fix the intake gasket.

I was out working on cleaning the frame up and getting a few more things ready to transplant and noticed fresh oil where I had cleaned. So I cleaned it again and went back to what I was doing. As the day got hotter, high of about 30 degrees C, the oil came back. I know that the heat was causing the oil to expand and that it needs to go somewhere, but it seems to be coming from the top of the engine. This engine hasn't ran in probably 3 years for sure so all the engine oil should be in the bottom end now, and the vents on both the transfercase and tranny are open, so it should come there first then out the top of the tranny.

What do you guys think it is? From what I can tell it is engine oil. Is there a place the oil could be caught up in in the heads and it is escaping from there now?

 

[1997chevydriver]

Only think I can think of if oil pressure sensor by dist. but like you said all the oil should be in the pan by now

 

[shelbyt.67]

If its on the DS it could be oil trapped in the oil pressure sender. Other than that, best guess is valve cover gaskets?

 

[JonZ71]

Are you sure the engine isnt full of water and pushing the oil up? I know it's unlikely but just sayin.

 

['89/'92Chevy/GMC]

Water is pretty unlikely, engine has only been exposed to the elements for a little over 3 weeks with a large piece of heavy duty plastic covering almost all of the engine.

I am hoping to pull it up next to the shop tomorrow and start pulling the motor apart and see where it is coming from. I can see oil sitting on the intake manifold on the drivers side, so it is probably oil pressure sender.

Thanks guys for your help.

 

[93 K1500]

There is also a Elbow on the very back of the motor that if it hasnt ever been changed it is plastic and a very common place that these motors leak If the motor is in the truck you can only see it with a mirror

 

[ChrisAU]

Sitting on top of the intake manifold? Sounds like its seeping up through one of the intake manifold bolts; mine was doing this when I got it. The middle 4 bolts on each side of the intake go throug the lifter valley and are exposed to oil. Over time the thread sealant can wear away and the oil WILL seep up through those bolts.

 

['89/'92Chevy/GMC]

Motor is in the frame but the cab is off. I got a gasket kit for the motor last night and we are going to open in up tomorrow evening and see what else we need for it.

 

['89/'92Chevy/GMC]

Got the oil leak figured out, seems it has had an intake gasket job once already. I know this because the dummy that did it came all the way across the back of the valley with silicone up to the oil pressure sender, stopped and started from the other side leaving a gap the width of a dime. Now it makes sense as to why it was losing oil.

however what do you guys make of this mess?

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The carbon build up is really bad, and I noticed there is no oil sitting in the low spots in the valley and the timing chain and gears don't seem to be getting enough oil.

 

[shelbyt.67]

Cheap Dino oil w/cheap filters along wit bad or old PCV units. Main cause of carbon deposits. U prolly got clogs everwhere too.