I've been trying to find a persistent oil leak that keeps coating the underside of my oil pan and back. I seems pretty clear now that the oil is coming from the seal at the bottom of the front cover. I'm very surprised to have a leak there because it's been tight as a drum for the past 3 years. Is this a normal problem that can creep up when the seal was once good? Or is this more likely caused by excess crankcase pressure (cleaning out the PCV system and replacing the valve didn't fix the problem) and therefore symptomatic of another problem, or do I just need to bite the bullet and reseal the front cover?

Thanks.

 

Reseal that baby!!!

 

I had the same problem and it came down to a leaking crank seal. I had to replace the balancer hub and the seal together and then the leak stopped. Oh yea, I replaced my crank position sensor seal while I was in there too - but that's only 1996+ LT1s (OBD2).

 

Have you ever removed the timing cover? If so it could be the waterpump seal. When Mine started leaking I went ahead and replaced all of the seals, since your in there anyway might as well. Make sure you put the new seal in straight, cause if it distorts it will leak, so use a big socket or pvc tube to hammer it on. The old one can be taken off be simply putting a screwdriver on the metal of the old seal and tapping downward it will distort very easily, no need to pound real hard, then simply pull it off with your fingers. This method is cheaper than buying one of those specialty tools.

 

I agree that your most likely suspect is the water pump seal and, it's the toughest to get in correctly. I seriously doubt it's the actual timing chain cover seal. The Crank seal is the easiest to replace but that damn water pump seal is a PIA and when it does leak, it oozes down and around and you'll swear it's from down low.

Ask me how I know? I changed the crank seal 3 times before I could be convinced it was the water pump seal because I could never see the trail of oil from above.

As mentioned, you need to be very meticulous about replacing the water pump seal because you can easily "roll back" the sealing gasket and it will never seal if you do. I found a very sweet trick that may help .....

Get ahold of one of those large, I mean giant, Sharpie brand black marker pens. Cut the plastic pocket clip off the cap and smooth it nice so there's no sharp edge left over (from the cut). This piece is now almost the exact size to set over the shaft and allows you to "ramp" the new seal right on without rolling it under. Oh yeah, apply a light coat of motor oil to the Sharpie cap to aide in slipping it on. This works better than anything I've tried.

Good luck!

 

I'm familiar with all of those seals from my head/cam swap in late '99. I really think this is the cover/oil pan seal. A friend of mine had the same problem and said that he gooped RTV on the outside of the seal and it fixed it, so I'm giving that a try for starters. If that doesn't fix it, then I'll look for possible leaks at the crank and water pump seal, but those areas at least _look_ dry. Thanks all.