My 94 Z28 has had an oil leak in the front since I got it 4 years ago. It looks like it's coming from the crank seal. The oil pressure is always fine so it's not pouring out, but it is messy every time I get under the car. The crank seal has been replaced twice, once by my Dad and once by me, and it doesn't help at all. The other seals in the timing cover have also been replaced, as has the gasket; no help. I had thought that maybe I was overfilling with oil so that the pressure was a little high and had to be spit out somewhere, but I'm only putting in the called for 5 quarts. Does anyone else have this problem? Comments?

 

Mines been leaking from there since I got the car...I just check the oil level every week and usually only add some every few weeks. Only bad thing is that its a little messy on the bottom.
Bill

 

its probably the intake manifold gasket in the rear of it. common problem with these cars. my coworkers trans am is leaking the same way

 

if it is from your crank seal on the front, could it be your harmonic balancer??

Over time the oil seal can cut a groove in the surface of the harmonic balancer and the lip of the seal cannot seal perfectly. Usually a new seal fixes it for a short amount of time and then the leak will start up again.

I know this is the case with the old SBC and your can purchase a balancer sleeve to fix that problem. I had to put one on my 350 in my 85 1/2 ton as the surface had a very deep groove.

see here for an example:

the second web site is the page where the sleeves are.

http://www.hi-performance.com/catalogue/index.html

http://www.hi-performance.com/catalo.../PG010-014.pdf

 

Thanks for the suggestion. But the LT1 has a different build apparently than the older small blocks. The harmonic balancer just comes right off the front of the crank hub, both of which are outside the timing cover and hence should never see a drop of oil. The crank seal is fixed in the timing cover and the contact it makes with the crank is pretty soft, too soft to ever wear a groove I would think. However, from your suggestion it occured to me that it may be possible for an improperly balanced assembly to maybe wobble enough to cause a leak. Mine isn't unbalanced as far as I know but I suppose it's possible. As for the possibility of a leak from the contact of the front of the intake to the block, I don't think it's coming from there and we have made sure to coat it good with RTV, but I will remember that and take a second look.

 

The crank seal is really just the same whether it is an LT1 or SBC. The difference is the LT1 has a two piece hub and pulley. The seal functions just the same.

My timing cover has been off twice. I changed the seals the first time (though they were not leaking). My engine is completely dry. You need to clean off the area and pinpoint where your leak is. Then you will have a better chance of solving the problem.

 

If your sure it's the crank seal make sure you put a thin layer of silicone around the outside of the seal before you seat it. Then you'll have a perfect seal

 

Does the car ever sit for 3-4 days without being driven. Mine will leak just a drop or two if not driven and whatever you see under there can just be an accumulation of many small drips over time.

 

It would be nice to have a dry engine for once. My dad is an expert and he says it looks like it's the crank seal, and now that I know enough to have a valid opinion, it looks like it's the crank seal to me too. It doesn't just drip oil, it spits it. All over the plugs and wires on the distributor, all over the inner side of the aluminum accesory bracket, etc. I wonder why mine would leak there but no one else's. All4Chevy's is leaking there but have you changed the seals? Maybe I'll try that silicon on the crank seal suggestion next time I have everything off, make it a little tighter.

 

I had a waterpump drive shaft and opti seal leak when i installed them with lube on the shaft and the opti drive. They say install dry for a reason Teflon and oil dont get along too well evidently. You migh try the UV dye in your oil route. Frankely it was the best $20 i ever spent. I have used it on several cars / trucks since works every time. No need to guess where it is leaking from let the UV light tell you