How do you replace the main seal in a 302 mustang?

Answer 1

If it's a newer motor with the one piece rear seal, you can leave the engine in the car. Remove the transmission. Carefully pry the old one out with a screwdriver. Push the new one in evenly. I use a piece of wood and a hammer, and move it around the circle while tapping lightly until the seal is fully seated.

If your engine has the two piece seal, you'll have to pull the oil pan and the rear main bearing cap. It's possible to do it with the engine in the car, but the front crossmember will have to be removed to get the oil pan off. Be careful not to scratch the crank while removing the old seal.

The front seal is much easier to get to. Remove the crank pulley and dampener. You'll have to rent a puller from the auto parts store. Pry out the old and hammer in the new.

Unless your main seal is just pouring out oil, or you've got a freshly built motor with a improperly installed seal, just keep checking the oil level until you can completely rebuild it. It's not worth doing all that work on a worn out motor. Also check your pcv system. If pressure is allowed to build up in the crankcase, it can force oil past seals and gaskets.