Ok, I have a 1995 Z28 automatic, with an oil leak. Not sure where it is coming from.
First I saw oil leaking around the timing chain cover thought the gasket took a dump. Put the car on the lift started pulling accesories off, when we noticed, oil running down around the timing chain cover from the top. Also found some oil running down the rear. we discovered it was most probably the intake gasket. Pulled the top end off, and low and behold the gasket had been reused when the last owner did the motor. Cleaned everything out,oil in all the valleys, it was a mess... new gasket, and a good bead of silicone instead of those garbage cork ends. Got the car together, let it idle for like an hour. Dry as a bone... (GREAT...WRONG!!!!)
Took the car for a drive, and jumped on it a few times (running great, awesome oil pressure, low temp) took it back to the garage , parked it, smoked a cigarette, and looked underneath... OIL EVERYWHERE. Didnt have time to get it back on the lift, cause it was late, but the back of the motor is where it appears to be comming from... Now I know what your gonna say REAR MAIN-SEAL... but I dont think so. when the car was up, before we did anything, that area was actually dry... what other possibilities are there.
I saw another thread where some guys said the plastic thing that hooks up for the oil pressure sensor broke, and spewed everywhere... but only one of them said his guage dropped to 0. Is there a possibility, it could be cracked orr the line ruptured, still allowing the car to read oil pressure, but leak ALOT of oil ,at the same time???
Someone please help me with a direction to look, I want to make pulling the crossmember and pan for the rear main seal to be the LAST option... list me other spots where oil can be leaking from????
PLEASE HELP!!!!

 

How long did you let the sealant dry before starting it up? What kind of sealant did you use? It's possible if it wasn't cured enough you may have blown it out.
It's a good idea to let the sealant cure for several hours before starting the engine.

 

I dont remember what brand it was, but it was what they use at the shop where I do all the work. Its a performance shop, and their parts and products are top of the line. I want to say it sat for the full nite when we got it back together. We didnt start it that night, because we broke the dry-rotted serpentine belt taking it off. So we waited till the am, ordered the belt, did an oil change, and completly flushed the coolant. My guess, about 12 hrs of sitting before restart.

 

I'd still bet on the beed of sealant failing if that much oil is leaking. Sometimes it can be hit or miss. Did you make sure when you set the intake down you did not move it after it was seated? You did say you cleaned off the oil from the engine so you wouldn't be seeing residual after trying to repair it?

 

I guess im gonna have to just get it in the garage and pull the intake again, and check the sealant and see if it blew out. Rear main seal leak would come from low on the motor , right, there is no way that would be leaking from up high??? I mean, oil cant walk up the back of the motor then spray out??? (what a dumb question... Im just getting sick of seeing oil on the ground ARHHHHHH!!!!!!!!!!

 

A rear main would be leaking out of the dust cover since it's w/in the bellhousing. You can always run your hand on the back of the block to see how high it's coming from. Feel around your steam pipe as well (connected to both heads from the rear right next to the intake/routes next to intake manifold on pass. side).
Make doubly sure the next time you do this that you scrape the block, front and rear very thoroughly. Use brake cleaner after scraping to get all finger/motor oils off the block before applying to block. Do the same for the manifold. When setting manifold down make sure it goes STRAIGHT down onto the block. If you want you can use some sort of make shift rods that fit into a couple of intake bolt holes on the heads to act as dowels to ensure the manifold is lined up before it actually touches sealant. Not sure how thick a beed you put on there, but I don't even bother with the plastic nozzle supplied (I use Permatex Ultra Copper or Black). I've always applied a beed that is almost the width of the seating surface on the block.

 

And that has been a "no leak" fix for u... in the past??? Damn I hate doing things over and over again....

 

Try this link for info
http://www.geocities.com/MotorCity/Downs/4013/ol.html

 

Oh God no! I really wish that page would just go away! It's a cancer...
Do not believe for a second the leak is caused by heat from the EGR tube. There is no need to wrap it.
That doesn't confirm sh(t.
DO NOT sand on your block! DO NOT put divots in your block! Neither of these methods help any more than just laying a good quality bead of sealant. The block surface is porous enough for the sealant to adhere onto the block. SAME with the manifold. If it weren't true then why do you have to spend several minutes w/ a razor blade/putty knife scraping sealant off the block? Inserting more peaks/valleys on the block surface can actually be worse because the sealant may not be able to get into all those little crevices where oil can!
Completely and utterly unnecessary. If you have enough pressure in the engine to blow out sealant that has been properly applied and cured then you have far worse troubles.

 

The last oil leak fix that I did was my water pump driveshaft seal. This is the top seal in the timing cover. I thought is was rear main, nope, then I thought crank, nope. It was wp seal, not too much fun installing.

 

Ok... got the car back in the garage.... back of the intake feels dry, but there is gunk behind the drivers side valve cover... guess Im gonna do those gaskets next.... What are the freakn odds, the intake and valve cover gaskets would both (all three) be leaking????

 

If it truly is the valve cover gaskets then that's a bit easier than having to remove the intake.
You might as well replace both.
However... did you take the valve covers off when you pulled the intake? If you did it's quite possible the gaskets aren't seated in the covers. Sometimes when placing the valve covers back onto the heads the corners of the gaskets can slip off the covers.
I would still replace them. The new ones will be quite smaller than the length of the valve cover. You'll have to stretch them out a bit in order to make them easier to work with. I always put fingers on all four corners of the valve covers holding the gasket in place when putting the valve cover on the head.