Washer in oil pan

[Boatwright]

if it's a steel washer and a steel pan you could for extra peace of mind put a magnet on the outside of the pan down low. It will trap the washer until the next time the pan is off. If there is a drain plug that doesn't already have a magnet, you can drill a hole and JB Weld a magnet into it.

This is an old trick used to capture fine ferrous metal that may have found its way into the pan. However, those who have posted not to worry are probably right.

[Tricolor]

99% of these pans still have a plug with a magnet inside, a remainder of their automotive/tractor past.

[hellosailor]

What Boatwright said. Except, I'd spend the bucks on a neodymium N42 or M50 magnet maybe 1/2" thick and 1-1/2" across. ain't cheap and they can literally BITE if you get skin between them and something magnetic. But if you wipe that across the oil pan a few times, so it snags the washer, wherever you leave it, that's where it will stay. That ensures the washer can't bounces up and get into any moving parts that are just being splash lubricated by the oil in the pan.

Probably totally excessive and not needed...but that washer might evolve into a gremlin, if given a chance.

[Compass790]

Ask the mechanic if it was a copper washer. Very good chance that it was if it came off an injection pump. If it fell straight to the bottom I agree with other posters about not losing too much sleep over it.
Wouldn't be the first washer found in a sump I can tell ya

[farmall.dude]

Originally Posted by hellosailor

What Boatwright said. Except, I'd spend the bucks on a neodymium N42 or M50 magnet maybe 1/2" thick and 1-1/2" across. ain't cheap and they can literally BITE if you get skin between them and something magnetic. But if you wipe that across the oil pan a few times, so it snags the washer, wherever you leave it, that's where it will stay. That ensures the washer can't bounces up and get into any moving parts that are just being splash lubricated by the oil in the pan.

Probably totally excessive and not needed...but that washer might evolve into a gremlin, if given a chance.

Nah, don't bother buying the magnets. Everyone these days has a dead hard drive somewhere. Pop that baby open and harvest the 2 magnets from there. Big ol' 5 1/2" drives are best. Bigger magnets! If you don't have one, ask around. Someone somewhere near-by has one.

[Elie]

Originally Posted by Kenomac

Just leave it there.

That is exactly what I would do. This washer won't do any harm to the engine, won't be sucked by the oil pump, won't get into bearings. I will just sit there as a testament of your mechanic incompetence...