mechguy79

Ok, got the engine out of the car (train wreck) to fix all the little annoying leaks. I was pretty sure I had a bad leak as I get splatter on the driveway if I rev the engine. Thought rear main, little damp, but clutch is nice and dry.

Well, pulled the motor and I see plenty of little leaks, but none major. What really bothers me is a couple of guys working with me suggested my oil leak may be coming from the back of the heads between the cylinder heads and block. Both cylinder heads have very similar oil trails down the block.

I am thinking the oil leak is the back of the china wall and the oil is walking down the seam and then down the block under the rear of the heads.

Question is which is more likely.

leesvet

IMO...either, or.

You will find many china wall leaks in the various corvette engines.... and you will find oil leaks from the OP sensor, or the other end timing cover. Front face is clean and dry?

If you get splatter then there is oil leaking onto something that spins...that's easy enough to spot...flywheel or a pulley? only YOU can see that.
if the engine is OUT...just fix 'em all.

C409

... There is no pressurized oil fed through the cylinder head deck surface or gasket ... all of the cyl head's oil is delivered by the push rods ... the only oil passed through the head and block is drain back oil at each end of the head ... the valve cover gaskets will leak as will the rear China wall ... another likely culprit is the oil pressure switch and sending unit and the tree they attach to but they tend to leak on the drivers side only .........

mechguy79

That's what I figured. Thanks for the confirmation. I've already got gaskets and "The Right Stuff". I will just do them all to be sure.

mechguy79

RTV nightmare. Well I stripped down the engine, pulled off the intake, and someone had put RTV on EVERYTHING! The intake gaskets were coated on both sides, and RTV had overlapped into the water jackets. It took over 90 minutes to clean all that crap off. Safe to say that was my main leak. I am replacing all the other seals while I was at it. Turns out the timing chain was stretched as well.

I used "The Right Stuff" on the front and rear china wall so we will see if it is worth the hype.

leesvet

Be careful...
I know of a story where a guy let some scrapings fall into the pan and the engine destroyed itself with the silicone chunks all sucked up in the oil pump pick-up screen... cruising along and suddenly ZERO oil pressure....OUCH !

cadmaniac

I'm gonna chime in here. I have a '94 Firebird formula (LT1) 6 speed. Leaked everywhere. Got all the leaks fixed (opti, waterpump, rear main seal, dip stick, oil pan, & intake. Yes it leaked everywhere. After all that the engine still leaked!!!

Over the next couple of weeks we used dye, andfinally figured it was seeping from a cylinder head on the first 1/4" near the intake. Just enough to create a small leak. I took a chance and cleaned it with a wire brush, brake cleaner, and then put a nice clean bead of permatex on the seam. There is no oil pressure there and it FINALLY sealed the last leak up. Next thing was to replace the head gaskets.

I have 3 friends that teach auto mechanics, and they all were mystified as to why it would leak there BUT IT DID!!!

DucXL

When i started to address my oil leaks on my '89 it led to engine removal too.which HAS led to a COMPLETE(engine and trans) overhaul.That started 8-12 when i'd only put a total 100 miles on it. Mine is a totally stripped shell of a car presently requiring another year of effort.Couple days ago i bought an identical '87 for $3k to bum around/w in the meantime.Makes a good example for the '89 reassemblie and a parts donor in the future.These cars don't age well and are poorly supported by the aftermarket

mechguy79

Well I got it all back together and in the car. I stuck to my target and only fixed leaks. Some buddies kept trying to convince me to do other "while you're at it" stuff, but I kept on target. I got the engine and trans all bolted back in and secure. I only had to do a couple of things that NEEDED to be fixed. The timing chain, the U-joints, harmonic balancer, CTS, and all gaskets. Took my time, tightened everything to spec, and all I can do now is finish assembling the top and fire it up.

kimmer

Good luck to you, hope everything is sealed up good.