Originally Posted By: Colt45ws
Yeah the pressure rating of the can is based on it being a circle. A dent creates a stress riser and can lead to failure.
I dropped a Ultra not to long ago while I was getting ready for a change. I was more than a little upset but I did end up getting another one.
They are mild steel cans, and under pressure from the inside, so either nothing will happen with the dent, or the dent will be popped out by oil pressure and then nothing will happen.
I would still use them, but just to be safe I'd inspect the filter after giving the engine a decent rev with cold oil to send the filter into bypass mode.
If the filter can was under vacuum or pressure from the outside, then sure a dent would be a big deal.