In article , "AL"
wrote:

I believe Swedes, Germans and Japanese spec thinner oil pans in order to
save weight. The thin metal can't withstand too much torque, so a crush
washer is required. This is also why you don't want to take your fine
Swedish, German or Japanese auto to the local quicky lube where the, uh,
mechanic, will use his trusty impact wrench to tighten the drain bolt.

I get my Nissan and Honda crush washers on the web for $0.20 to $0.30 each.
I buy them about a dozen at a time, along with the filters.

Pep boys sell them fairly inexpensively. Measure the ID and OD and see if
you can find something similar. The ID needs to be very close, but the OD
can be larger.

I don't understand why a felt or rubber washer wouldn't work. The oil pan
isn't under pressure. At most you'll leak a few drops.

The problem is that without the copper washer, there won't be enough
tension on the plug to keep it from backing out under normal vibration.

This happened to me once, when the dealer screwed up an oil change.
Fortunately, I was going at highway speed, and so the oil plug bounced
on the pavement and struck the bottom of the car quite hard, waking me
up in time to save the suddenly oil-free motor.

Joe Gwinn