How do you replace rear main oil seal for Chevy 4.3 L?

Answer 1

Welcome to the life of anyone who owns a GM 90 degree V engine. Those and intake manifold gaskets are two recurring problems.

First, ask yourself - are you mechanically inclined enough to do this? I mean, you asking this question on here kind of makes me wonder. Not trying to be patronizing here, I just don't want you getting in over your head.

First thing you're going to do is ensure that's where your oil leak is coming from... there are several locations on that engine where it could be, rather than the rear main seal. Drain plug, oil pressure switch, oil filter (especially if you have the remote oil filter), oil cooler hoses, clogging of the head return oil ports (allowing oil to leak out around the valve cover gaskets), oil sender, distributor gasket... all possible locations for an oil leak. I'd recommend you wash the engine and engine compartment thoroughly with a degreasing agent, add a UV leak detector dye to your engine oil, run it for about a week, then check over the engine with a black light.

If it is the rear main seal, then you'll have to remove the transmission and transfer case. You'll need a transmission jack for this (it's possible to rent one). Once you've gotten the transmission and flywheel off, what I usually do is drill a small hole in the outside of the seal (1/16", typically), then drive in a drywall screw to pop it off. Once that's done, you clean the area, drive in the new seal evenly, then reassemble everything.

My email address is in my profile page if you need additional help with this.