Chadwick

iTrader: (12)

The two points of failure that I have found are the paint on the oil pan and the gasket. Every stock motor I have taken apart the paint has separated from the pan at the point of the leak and the gasket is also cracked. I would speculate that the oil, heat and constant flexing eventually cracks the paint and gasket and the leaking starts.

I use a similar technique as Dave and stay away from using a gasket. It has been my experience that the gasket gets brittle with age and cracks from the slight movement of the housings.

I strip the paint off the inner 2/3’s of the oil pan, clean both surfaces with acetone, apply a thin layer of RTV on both mating surfaces and torque to spec. After I let it dry for 24 hrs, I re-torque the bolts.

jacobcartmill

iTrader: (6)

do you get the RTV coming out of the bolt holes when you tighten the bolts?

DaveW

I had a very small amount come out of a few bolt holes when I did mine. I was pretty careful not to use too much sealant. The 3/16" bead seemed to do the job quite well.

Dave

dgeesaman

iTrader: (7)

I believe that's why dimpling works - it permits a layer of sealant of substantial thickness, which helps tolerate expansion / torsion of the components without tearing the seal. The high points of the dimples are what transmit the clamping force of the bolts and therefore maintain solid metal-metal connection.

Without dimpling, the amount of sealant in between the surfaces is so thin it can be damaged easily.

Dave

DaveW

In addition to what you said, the "dimples" or "crater rims" around punch marks (which is what my pan "dimples" were) tend to dig into the aluminum sections, and somewhat lock the pan to the engine, helping to prevent movement and seal degradation.

Dave