Oil Pan Gasket
Senior Member
Joined: 02-01-2006
Posts: 1,471
From: lockport,ny
The problem with using a gasket to seal two flat surfaces is the gasket has a tendency to slide out between the screws.
Notice the gaskets that are on the engine (timing cover, valve cover, etc) fit into a designed recess or have a metal layer to keep the gasket from deforming.
Also, most modern engines use the oil pan as a structural element for the engine, which might explain why they don't use a gasket on the oil pan. In the old days the oil pan was a stamped steel pan just hanging off the bottom of the engine to hold the oil. The cast aluminum pans add rigidity to the block and help vibration. A very thin silicone layer allows the pan and block to mate together tightly. A gasket would act as an isolating layer, allowing some movement (even if the movement is very small).
Steve
Notice the gaskets that are on the engine (timing cover, valve cover, etc) fit into a designed recess or have a metal layer to keep the gasket from deforming.
Also, most modern engines use the oil pan as a structural element for the engine, which might explain why they don't use a gasket on the oil pan. In the old days the oil pan was a stamped steel pan just hanging off the bottom of the engine to hold the oil. The cast aluminum pans add rigidity to the block and help vibration. A very thin silicone layer allows the pan and block to mate together tightly. A gasket would act as an isolating layer, allowing some movement (even if the movement is very small).
Steve
Platinum Member
Joined: 12-06-2009
Posts: 11,721
From: Alabama
It ain’t rocket science ! Clean the pan mating surface. Clean the lower block mating surface. A thin bead of sealer on the pan surface. Let it “sit” till it dries a little. Carefully install pan. Tighten bolts uniformly and torque to spec.
Senior Member
Joined: 12-05-2014
Posts: 3,370
From: Northern Ohio
Exactly. The specified product is GM's 12378521 RTV, and you can by a tube for about $12 shipped, but I'm sure any reputable RTV will be fine.
RTV adheres well enough that it's plausible that the pan adds to the block's stiffness. (Easy! I only said plausible, didn't say it's so.) That would be less so if silicone or a gasket were used.
The tricky thing would be to make sure the block mounting surface is oil-free. Easy in the production facility with an inverted engine. Under a car, not so much.
RTV adheres well enough that it's plausible that the pan adds to the block's stiffness. (Easy! I only said plausible, didn't say it's so.) That would be less so if silicone or a gasket were used.
The tricky thing would be to make sure the block mounting surface is oil-free. Easy in the production facility with an inverted engine. Under a car, not so much.
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