When installing new style rubber oil pan gasket on old style pan, should I grind off the raised metal around the bolt holes or use a hammer and dolly to flatten the pan? Does it matter which I do? Grinding undoubtedly easier, but hard to go back once done!

 

I have only read about people grinding them down. However, if you can make the mating surface flat with hammer/dolley, then that should work.

 

Grind it is! Thanks

 

You run a higher risk of distorting that mating surface with a hammer and dolly than you do with a grinder - you are basically pushing the metal around, and it tends not to want to move without distortion. At minimum, I would make sure the pan was set solidly in place and instead of using the hammer directly onto the pan, I would get a long drift with maybe a 1/4" flat tip and use to to localize the impact as much as possible.

 

Yes, thanks. I will grind it flat.

 

Good call. Having done it more than once, I don't even think you could properly pound it flat if you wanted to. Those ridges would have to go somewhere and would probably end up splitting or spreading improperly. And, as HoustonDave said, you'd probably warp and distort the whole thing.

I think it took me 10 minutes to grind them off, so it really isn't a big task.

 

Yes, upon further review, it was probably a poor idea to even contemplate using a hammer and dolly.