No gasket sealer on rubber?

[bjde0b]

My Tom Monroe book states not to use gasket sealer on the rubber rear main seal or rubber seals of the oil pan. I know that the silcone was originally meant as a gasket replacement, but we all use it anyway for insurance. Is there a reason not to use it on the rubber? I haven't, but it makes me just a bit nervous.

[70_F100]

A (VERY) small dab at the ends of the rear main seal is good insurance, but make sure that it doesn't get on the lip portion of the seal. In fact, if you can put the upper half of the seal in, then before installing the rear main cap, put the lower portion against the upper and turn the whole thing about 30-45 degrees, it helps seal the ends. That way, you don't have the ends of the seal meet at the same place the cap meets. Then, put a small bead on the block mating surface of the rear main bearing cap before you install it. That will take care of any irregularities on the block or bearing cap.

On the rubber oil pan seals, put a dab where they meet the cork gaskets. If the engine is in the truck, you can use a very small amount of a good, non-hardening weatherstrip adhesive to hold them in place.

Anywhere multi-piece gaskets form a joint, a SMALL amount of silicone (I prefer the original black) is, as you say, insurance.

Keyword: SPARINGLY!!!