Rear Main Seal

[eso123]

'98. 4.0L. Manual. 172k miles. Original owner.

Problem: Leaking rear main seal. New silver-dollar-sized oil spot on the garage floor after sitting for ~24 hours.

Two questions:

1. Has anyone tried product like Bar's for "sealing leaks in the rear main seal?"

2. The clutch is original and will need to be reconstructed somewhat soon. How much more work is involved in replacing the rear main seal as part of the clutch job?

The idea is to somehow "seal" the leak until the clutch goes and do both jobs at one time.

Thanks for your comments. This is a great forum.

[pcollins]

I've heard a lot of good things about bars, haven't tried it. I would like to give it a shot on my F150. it has a rear main leak and like you i'm waiting for my clutch to go before fixing it. 90% of the time the flywheel should be removed to resurface it and get a new pilot bearing anyways, and the rear main seal is right behind the flywheel, so it really isn't any extra work at all.

[jhammel85]

^ Yep. The above sums up what I was going to say.

However, I would stay away from Bar's leaks. I know it kinda works from what I've heard but my personal opinion is that the "fixall in a bottle" stuff is crap. It's best to just fix it, you know?

Good luck with it! Sounds like you've had plenty of time behind the wheel of that faithful truck.

[ragajungle]

depending on how bad a leak it is you may not want to wait too long. Eventually the seal will wear down and the tiny tension spring moulded into it will start scoring the crankshaft output and any seals you put on after that will premie ware out.

[Big Jim M]

99% of rear mail seal leaks are from blowby pressure building inside the engine.. This can, most times, be repaired by SIMPLY installing a new pcv.. The pcv in older engines should be replaced with EVERY oil change!
Clean the vent system...hoses valve and whatever there is.. See what happens.
Big JIm

[eso123]

All good points, especially not delaying the work to avoid scoring the shaft itself and replacing the PCV, which needs to be done anyway. Thank you all.

[TrexMex]

I have heard that it is a good practice to replace the rear main seal when doing a clutch job since you already removed the flywheel for resurfacing anyways. About bars leak, isn't that something you don't want to put in your engine if you care about it?

[sholzy]

Originally Posted by Big Jim M

99% of rear mail seal leaks are from blowby pressure building inside the engine.. This can, most times, be repaired by SIMPLY installing a new pcv.. The pcv in older engines should be replaced with EVERY oil change!
Clean the vent system...hoses valve and whatever there is.. See what happens.
Big JIm

+1 on replacing the PCV. I know first hand on the difference it makes.

[sholzy]

Originally Posted by TrexMex

About bars leak, isn't that something you don't want to put in your engine if you care about it?

I don't think i would want to put something in my engine that is intended to plug holes.