Shoebox you are an absolute joy to have on this board. And before I go much farther let me say how much we all appreciate the info you've made available to this board.

While I'm actually not afraid to replace my non leaking RMS, (yep, despite your earlier admonishment about things having to be replaced "correctly" I'm really pretty SURE I could do this ), what invariably will happen is this:

If I don't replace my "old" RMS ..... then like you and Compstall have implied, it will begin leaking 15,000 miles down the road, and I will say to myself ...... "You dumba** ..... why didn't you replace that RMS when you had this all apart 15,000 miles ago".

If I do replace my non leaking RMS and the NEW one leaks .... I will say to myself .... "You dumba** ..... why did you even think of changing that perfectly good RMS you had in there". See what I'm dealing with here.

If anyone who has either already replied to this thread, or anyone else "out there" has any good advice and/or experience with LT1 rear main seals ...... I'd appreciate you sharing your input. Again, Thanks! to all who have, or will, reply to this.

 

It boils down to where you see the chances in your favor.
Scenarios:
Seal not replaced. Odds of leaking soon-higher than with a new seal.

Seal replaced. Odds of leaking soon-low (as long as the installation is well done).

I replaced mine when the engine was out (around 95K). No leaks after 15k miles.

 

Just replaced mine when I installed my converter. It was easy and these things like to leak so why not? It's always better to replace parts when they're hard to get to unless you have other parts out for access. Just my opinion.

 

Okay, now you guys have me leaning toward replacing it. I know you just "pry out" the old seal from the RMS housing with a screwdriver, but, ...... what do you use to "set" the new seal in place??? A piece of 4" PVC pipe??? I know GM shows a "special tool" for doing this, but obviously, I won't have that.

 

I just tapped it in place a little at a time going around the perimiter of the seal. Getting it started is the hardest part. Just be patient and lightly tap it.

 

I have a large round 1/4" thick piece of leather I use w/ a deadblow hammer for knocking in seals. Works great.

 

Okay guys, just "closing the loop" on this one.

I just got my car back on the road today after doing my clutch and flywheel replacement, and I did replace my old OEM rear main seal.

Like everyone who advised me to replace it had said, it really took only about and additional ten minutes to do and, even though it wasn't leaking ........ I was sooooooooooo ...... glad I replaced it.

After removing my 11 year old, 81,000 mile, OEM rear main seal, I looked at the inside of it near where the two inner sealing "lips" are and ...... wow! ....... I couldn't believe it wasn't leaking. The inner portions of the seal were severly cracked and, it looked like ... dry rotted(???). Maybe it was just "heat checking" from all the thermal cycles the car had been through in 11 years and 81, 000 miles of driving but, it sure looked like that seal was really just "on the verge" of being a "gonner".

Thanks to ALL who replied to this thread, and if my experience is any example, I would STRONGLY suggest to anyone doing a clutch and/or flywheel replacement ....... to also replace that RMS while they are in there.

 

I'm replacing the rear main seal and I see a groove in the crank journal. Did you guys see this on yours?

 

In a word ..... no. I did have some "oil staining/oil build up" on the crank sealing surface, as I remember, (keep in mind I did do this job just over a year ago now), but I just cleaned the crank end with Gumout carb cleaner and a soft cloth and ........ the "oil staining/oil buildup" disappeared.

Try cleaning the crank sealing surface with carb cleaner and see if what you are calling a "groove" disappears. Once cleaned, drag your finger nail over it and see if you can actually feel a groove there. Do remember to lubricate the new seal with plenty of clean motor oil before installing it, and Good Luck! with it. (My new RMS continues to be leak free for over a year now).

 

I'll try cleaning it and see what happens.

 

If there is a groove, use a repair sleeve.

For example, Felpro pn 16258.

 

The "groove" did clean up. I can still see where the seal was, but can not actually feel it.