I’ve done a lot of oil changes on my all cars since the mid 80s. I have never replaced a washer on a sump plug. I’ve always reused the one that came off the engine. Most of the time it’s been a copper or fiber type washer. I have never had an oil leak from any sump plug.
I believe if the plug is overtighened, for sure you will need to replace the washer at the next service. I used to tighten the plug till it felt ‘just right’, whatever that really means – snug plus a quarter turn, or thereabouts. Nowadays the plug gets torqued to spec.
Thinking back, I did have to make a washer out of a fiber type material one time, which I kept reusing since it worked, and was suitable material. It was ugly, but hey when you have the will but not the budget, you just automatically resort to workarounds.
It’s only when I saw Scotty Kilmer say you should replace the washer every time, I started questioning my whole life.
