hi. does anyone know how to tell whether a rear main seal is blown or not?





i've got oil leaking from the area, so it's either a leaking oil pan gasket or a leaking rear main seal. i've taken off the inspection cover, but i can't tell which one is blown.http://www.dieselplace.com/forum/smileys/Confused.gif any recommendations???





thanx!!http://www.dieselplace.com/forum/smileys/Approve.gif

usually if its a rear main seal, common in 6.2/6.5s, when you fill the oil to the top of the dipstick, it will lose the first quart pretty fast, putting you at the bottom of the 'safe' zone, and pretty much stay there. Oil pan leak will be more consistent leak all the time.

I'm attempting to change out my rope type rear main seal on my 82 6.2. Can't figure out the trick to getting the seal in the block groove.
Does the crank need to come out?

Thanks for any advice.

When I did mine I removed the rear main bearing cap and loosened the one just forward of it just enough that the crank dropped to take the pressure off the seal. In my case there was only 3/4 of an in. of seal left in the top half and none what so ever in the lower half. I used a piece of #12 cooper wire to push up and over the crank to push the old seal out. Cooper is soft and will not cause a problem. With the crank dropped a little and lub on the seal it just pushed up into place.

I think most likely the oil pan gasket is leaking. GM has a weird way of sealing the back of the pan. A small piece of rubber is all they have. I would drop the pan to do it. If you have four wheel drive the front axle needs to be rotated slightly forward to get it down.