3.0L Rear Main Oil Seal Replacement Procedure

[ElginO]

I'm wondering how to go about replacing the rear main oil seal. I've got the motor out and oil pan is off, but do I need to remove the rear main oil seal retainer? The reason I ask is because I've got the oil seal but not the gasket for the retainer, so I'd rather not remove it unless necessary. The Merc manual doesn't specifically say to remove the retainer, but rather shows 3 spots to pry out the old seal.

Anyone have a backyard mechanic trick for driving the new seal into place, without the proper tool and with the retainer still on the engine? I went to harbor freight today, but could not locate a seal driver that was big enough (needs to be 4.5" o.d.). I would just buy the dang gasket but it's not available locally and I'd rather not wait for it to arrive in the mail.

 

[alldodge]

I'm wondering how to go about replacing the rear main oil seal. I've got the motor out and oil pan is off, but do I need to remove the rear main oil seal retainer? The reason I ask is because I've got the oil seal but not the gasket for the retainer, so I'd rather not remove it unless necessary. The Merc manual doesn't specifically say to remove the retainer, but rather shows 3 spots to pry out the old seal.

Anyone have a backyard mechanic trick for driving the new seal into place, without the proper tool and with the retainer still on the engine? I went to harbor freight today, but could not locate a seal driver that was big enough (needs to be 4.5" o.d.). I would just buy the dang gasket but it's not available locally and I'd rather not wait for it to arrive in the mail.

:welcome: to iboats

Go to a hardware store and get either a piece of 4 inch PVC pipe or fitting. Cut it square and place a block of wood on the back side so you can tap it in with a mallet.

 

[ElginO]

Thanks AllDodge! I'm glad to finally be contributing to the forums, instead of just lurking in the shadows!

So just to confirm, you don't see any reason I can't leave the retainer in place on the block, pry out the old seal and drive in a new one? Should I not worry about the old retainer gasket leaking at some point? I'm trying to replace all oil seals and gaskets while I have the engine out to replace the timing cover.

It actually occured to me last night that 4" PVC pipe would make the perfect seal driver for this, because pipe is measured by the inside diameter, which means the O.D. is right about 4.5".

I took the oil seal with me to the hardware store and found a 4" ABS pipe clean-out fitting with cap. The cap has a raised square block in the center, which should be a perfect spot to strike with a dead blow hammer, when driving the seal into place.

I'm thinking that this will make the perfect tool to allow me to install the oil seal with the retainer still installed on the block, the inside diameter of the pipe is just larger than the I.D. of the oil seal, and the O.D. of the pipe is just smaller than the O.D. of the seal. Looks like extra care will have to be taken, to not drive the seal in too deep, stopping when it is just flush with the retainer, but that shouldn't be too difficult.

 

[alldodge]

So just to confirm, you don't see any reason I can't leave the retainer in place on the block, pry out the old seal and drive in a new one? Should I not worry about the old retainer gasket leaking at some point? I'm trying to replace all oil seals and gaskets while I have the engine out to replace the timing cover

I've done several seals in such a manor and have not had any issues. That said, I have not done one on a 3.0L and I cannot see what your seeing. Don't see any issues all the same, as with most seals, if they were not leaking to start with, they shouldn't start leaking afterwards unless something changed during disassembly/assembly.