C4Scoreand7YearsAgo

I'm in the market for a Z06 and I looked at one yesterday and the bottom of oil pan was wet with oil. It wasn't dripping or anything, just a light layer of oil covering it. I couldn't tell where it was coming from. How normal is this for a 10 year old Z? Would you buy Z with a very slight oil leak?

n00b

mine has no oil on the bottom nor does it leak

JETninja

Mine had a few drips I noticed after I brought it home. (got it last August) turns out the Oil filter was not very tight....No more leaks...

pluslt

Mine does not leak a drop as far as I've ever seen. And with stamped concrete underneath me it would be easy to see.

As for me, no I would not buy a car with an obvious leak. Too many out there without issues to buy one that already has evidence of something. Could be that the owner knows there's a leak and cleaned everything up before you came to look at it and what you see is just the tip of the iceburg. Could be nothing, could be something.

Good luck.

mph1972

Sounds like a slow oil pan gasket leak. I would clean it up really well with some brake cleaner or something like it and drive it a few days and see what happens. Could better determine what it is. That is, if you buy it.

The gaskets aren't too expensive through ROCK AUTO or PARTS TAXI, but the upper pan gasket will be a PITA to swap.

CordMcNally

There's several things it could be:

1.) Oil Pan Gasket - pretty rare for them to leak, usually they just need retorqued back down. An easy fix.

2.) Oil Filter - most likely loose if it's leaking. Retighten it.

3.) Oil Pressure Sender - mine leaked and it ran down the back of the engine into the area you're describing. This is the harder fix out of the 3 but it still isn't a tough fix. Hell, you'll probably have to do this fix at some point while you own a Vette anyways.

4.) Rear Main Seal - this is the least likely and also the most time consuming to fix. It's a cheap part but there's a lot of labor involved in replacing it. Again, this is pretty rare on our cars.

I wouldn't rule out a vehicle just because it has a few leaks. Most leaks are minor and very easy to fix. I'd use it as a price negotiating tool if you're otherwise interested in the vehicle.

Ngineer

My '03 Z06 had only 4,461 miles on it when purchased. The oil pan had a light oil film from gasket leak probably due to sitting. Gaskets replaced, no more leaks there now with 9,500 miles on it.

Rear axle seals began to leak too. Replaced at about 6,550 miles. Fine now. Point is that cars with little use develop leaks. Is this a possibility for the car you're looking at?

C4Scoreand7YearsAgo

It had fairly low miles, which I think probably contributed to the leak. It was pretty minor, but did look like it could be from the oil pan gasket, and probably just needed to be re torqued. Its a moot point now because it sold to someone else. I do appreciate the info though, since I'm still in the market and now have a better idea of what to expect.

aquachuck1

Oil pan was wet on my 02 Z @60K......I checked it out and it turned out to be the oil seal on the timing chain cover.

BLKWDWZ06

my advice, have it cleaned and follow the trail

Xx_Black-out

My '03 doesn't have any leakage...I agree with the above. Clean it and re-check.

...and @ your username

bigblock1974

Which gaskets did you replace?

Ngineer

The upper and lower crankcase gaskets (required front cross frame removal). That stopped leak on crankcase then. Now, leaks again. Not sure what the problem is. Looks like could be crankshaft front seal. Car going to certified Corvette tech tomorrow.

Previously: replaced differential seals on both sides (only leaked on one side). Hydraulic clutch slave unit failed. Replaced it and installed a Monster clutch with lightweight billet flywheel. Hydraulic slave unit for clutch has improved seal design over the original part. Everything there (clutch) seems fine now.

Driver side rear axle spewing what appears to be black grease. Looks like a molybdenum disulphide type EP grease. Mechanic will evaluate this too. I'll update thread when I know what's going on with the crankcase oil leak and with the rear axle grease problem.