Blankety-Blank Rear Seal!!!!

Jeff Scherb did pass the time by typing:

If that hole plugs up you get excessive pressure build up in the engine and that can help push oil out the seal.

Or something like that.

I understand that, but the hole where the PCV valve connects is abouy 5/8"? Are you saying that size hole gets plugged somehow?

Nope, and that's a GOOD thought. The two PCV elbows are clear and all, however I never thought to open the manifold port up. I'll give it a look tomorrow.

No, he isn't. There is no PCV valve in the ordinary sense. There is a small orifice, about 1/16" diameter (very roughly) that meters the crankcase vacuum. This is what gets plugged. Pull the plug out of the valve cover and have a look see.

Regards,

DAve

Wow, are you using RTV on it and not letting it cure for the required 24 hours before adding oil or something?

Mike

Jerry McG wrote:

I've always used RTV, or in this case, the factory recommended anaerobic sealer on the main cap edges. It's dry as a bone right now, but I have no faith it will hold long before it starts to drip again. The book calls for Loctite 515 as the sealer to use on the main cap, but the Permatx Anaerobic sealer is the same stuff and a factory recommended alternative. There's conflicting sentiment on the use of RTV on the main cap, the factory says no, but some sources like Haynes say yes. Whatever, RTV doesn't work well on this engine. The seal that came out looked as good as the new one. The only sign of seepage was a tiny bit on the bottom of the main cap at the seal edge. But, this may simply be where it collected before ending up on my garage floor!

One other thought, Mike. The factory manual calls for a "3mm thick bead" of the anaerobic sealer, placed from the center of the bolt hole, along the edge of the cap right up to the edge of the tabbed ear on the lower seal half. That can be misleading, they mean (according to a Jeep tech buddy) to make the bead 3mm TALL, which is a lot of sealer. Compression of the stuff when the main was tapped into place and torqued down made it ooze under the seal at the ends.

Frankly I just think this is one block where the seal clearance is too loose. Compared to any others I've done the upper seal half pops right out when pushed on. Others I've done may require loosening one or two other main caps, not this guy.

As for the size of the leak, it';s not like it's a gusher. This ewngine doesn't use 1 qt between 3000 mi oil changes, just makes a mess on my garage floor.

Maybe it's time to swap the rear bearing for a new one.... How is the oil pressure. If the pressure is low or really swingy, that is a sign of a worn main bearing.

I am always picky and aware of drying times. RTV is tricky. If it doesn't get it's cure time, then it is a 50/50 crap shoot for leaks.

I even use big spot lights and heaters on areas for 24 hours that have RTV to cure if the temp is below 'room'.

Mike

Jerry McG wrote:

Oil pressure is excellent, 50 - 55 lbs at cruising rpm depending upon oil temp. 25lbs+ at hot idle.