I find this discussion about sealant Vs gasket interesting.  My "Plugs Up"
installation has the engine sitting on  its side, so naturally the oil flows
right across the seam of the oil pan and block.  I use the Red RTV sealant
for sealing and have for six years.  When I tried (early on) a gasket, I
found that the gasket eventually soaked through and dripped.  So I guess I
am really surprised that with the engine in its normal orientation (with the
oil pan on the bottom) that some are having problems with leaks.

I would suggest a close examination of the fit between pan and the mounting
plate.  One way is to stick a light bulb in the oil pan (remove oil first)
and then put the pan on.  If you see any light around the seam then you may
have a dented, ding or mussed up surface causing the leak.

Ed

I use 100% GE silicone tub and tile caulk. Never had a leak but have seen many. Adding sealant to the gasket sometimes pulls out some of the assembly sealant from between the iron and aluminum housings. Apply a bit of sealant at each junction between iron and aluminum. Also, the front cover gasket (if used) must be trimmed to end exactly at the gasket surface of the pan. Too short or too long and it leaks.

 

Sealant must circle every bolt hole top and bottom of the gasket, or the gasket will wet out as above and oil will appear under the pan bolt heads. You can stop it by removing each bolt and cleaning in Lacquer thinner, then a little band of silicone around beneath the bolt head. Let it gel up a while before installing. If you have the pan flange doublers, seal under those holes as well.  Pan bolts get loose after a time. After a number of hours, Retorque the bolts several times, then after the last event. Safety wire them. 

 

You can apply silicone and many other sealants with cheap kids paint brushes. Does the job, looks real good. Big stallagtites of silicone are interesting to children, but do nothing for our cause.

 

Lynn E. Hanover