Slowing Leak from Rear Main Seal

[92saturnsl2]

As the title suggests, the rear main on my truck has gone from annoying to being a real problem. For a long time, I could tell it was leaking (oil dripping from inside flywheel inspection plate), but I could never observe it dripping while running, and I only had to top up the oil occasionally.

Lately it's going through a half quart every 2-3 days (300 miles or so) and is beginning to have the burning oil smell while stopped in traffic, from oil getting on the hot exhaust. I have no idea what caused it to go from a slow leak to a rather quick one, but I did notice that on my last top-up, I put about 3/4 a quart too much in. Could the oil level in the sump make the leak worse?

What kind of band-aides exist for slowing a leaky seal? I bought a new seal and intend to change it soon, but have to wait for a weekend when the weather is decent. Luckily the transmission doesn't have to come out, but getting the oil pan off looks to be a real chore with the crossmember being so close to it. Anyone replace the RMS on a 460, if so, how long do you think it will take?

Any ideas, suggestions on how to slow the leak, or any other helpful info would be appreciated.

 

[Chris142]

Try the Maxlife oil. If that don't work then you gotta put a seal in it.

 

[crazyoildude]

Try high mileage 10w30 or 10w40 i use pennzoil and had great luck with it...That 460 is a pain to change when the engine is in the vehicle when it is out its pretty easy

 

[ram_man]

Ive actually used the rislone rear main seal stuff and it worked perfeclty. May gibe it a shot.

 

[paulo57509]

Half quart every 300 miles isn't exactly slow.

However, I've had good luck with Berryman B-7 Chemseal. It's mainly for automatic transmissions but it can be used in engines as well. Its worked for me.

 

[supton]

Does this have a rope seal? I had an 2.8L S10 with a rope seal, and when it was gone, it was gone. Replacing was a pain but I wonder if it would be easier on this--probably not, the 4x4 stuff is in the way I bet. I was able to pop exhaust and drive shaft, remove radiator IIRC, and yank it up just enough to get the oil pan out so I could get to the cap.

Was not a fun job...

 

[92saturnsl2]

The 460 had a rope seal at one time, but I think they abandoned that in the late 70's or early 80's. The replacement seal I bought is a two piece rubber dealy, which is what I suspect I'll find when I open it up. Either way the rope seal can be replaced with this new rubber one without too much extra effort, or so I've read.

4x4 stuff / front driveshaft doesn't seem to be in the way, it's that huge crossmember that completely hinders access to a good 2/3 of the oil pan. I was able to get to all the oil pan bolts a few months ago (tightened them all, thinking that could be a source of the leak) but it wasn't fun. Took a u-joint, lots of different sized ratchet extensions and lots of blind turning where you weren't really sure if you were getting the bolt head or not.

I suppose I can raise the engine off its perches maybe.... Either way I've got two days this weekend to do it, and it's gotta get done! I was sure hoping it would hold out till Spring, but such is life.

 

[Cujet]

It's worn out. Nothing will "fix" it. Even oils with "Seal Swell" only swell the seals a tiny fraction.

If you can, use a "Speedi Sleeve" on the crankshaft prior to installing the seal. It will ensure the worn crank does not continue to cause a leak.

 

[supton]

I've always wondered if that "seal in a can" miracle stuff would just prematurely wear out any other seals in the engine.

Good luck. IIRC mine was done with a bit colorful language. I was also younger, and dumber, and willing to bend a few things that got in my way...

 

[hattaresguy]

When they get that bad the seal is usually torn. Just keep checking the oil and try not to drive it much.