I have, kind of...

Ages and ages ago I redid a head on a friend's ford pickup, 240 six. When it came time to install the valve cover, I found the gasket in the kit was fragmented. I needed to get it together so I carefully ran a bead of silicone around the gasket surface of the valve cover. I let it sit until it had skinned over, then carefully placed it on the engine using the valve cover bolts for guides. So it was just resting on the head surface, bolts weren't close to being tightened.

The next morning I got in it, drove away and returned the truck to my friend. I forgot that I needed to tighten the bolts.

Three or four years later the valvetrain started to clatter and he brought it over for me to see what was wrong. As I started backing out the valve cover bolts I noticed that none of them was tightened, the heads were 1/8" or so above the valve cover. It hadn't leaked a drop, just sealed by the silicone. Keep in mind this is parts store blue silicone from around 1982.

There's no reason you couldn't do the same thing on an oil pan. Be conservative with the amount of silicone you are using, and use oil-resistant stuff.

Actually for this application I'd strongly suggest The Right Stuff. It cures immediately upon tightening and is what the factories use on the assembly line. I used it for end seals on an intake and literally drove away as soon as I had put wrenches away. NEVER LEAKED A DROP. It was the factory gasket on my '93Suburban's rear axle cover plate.

Someone will soon be telling you it's a bu&&er to get apart, but isn't that what you want? I use a putty knife and mallet to break the seal.

I cannot imagine using silicone on both sides (or even one side) of a gasket and making things better than they were with NO silicone. I hope Mr Superformance Gasket comes on board and reminds us that gasket makers work very hard to make gaskets that seal, and any uninformed messing with the gasket surfaces is just flat wrong.

I can't get over the thought that we pay good money to buy good parts and then think we're smarter than the outfit that made the parts.

R.