What is the most leak free drain plug washer to use on a stock oil pan? I have a mopar reproduction hemi oil pan. I think it uses a 1/2" id washer. The plastic washer that came with it had a slow drip. I tried the rubber/steel washers from autozone and they leaked too. Copper works okay but not as good as the steel washer than I had on my old 440. I haven't been able to find a place that sells the copper washers in bulk and usually have to buy a variety pack of 3 to get the size I need.

I posted a thread on this awhile back. General concensus was copper. Since then thats all I use, but I have had good luck with the hard fiber ones too.

I'd suggest another drain plug

One of the local parts stores (not a chain) sells a copper washer with an O-ring in the center. The copper allows you to tighten it so it won't fall out and determine the proper amount of crush for the O-ring. Works good on problem oil pans.

I have used aluminum washers with good luck too (aftermarket or from the Toyota dealer).

I have a new toyota gasket if you need one. Just send me your address and I`ll mail it to you. Mike

I wrap the drain bolt with plumbers tape and then use a solid rubber gasket from ACE Hardware. I tighten it until the rubber gasket just barely starts to squish out from under the bolt head.

The plumbers tape should cure any leak no matter what gasket you choose to run. I like the rubber ones since they are soft and won't cause the paint to chip off.

The plastic washers eventually yellow, dry up, and split. The rubber ones also dry out after about a year or so, but they are 10 cents each so I just buy a small bag of them and throw them in the tool box.

Aluminum or copper seems to work the best. The plastic ones work fine at first but then after a few heat cycles they start to leak.

Thanks guys, I've tried a Dorman rubber/steel one and it leaked for me. Maybe I overtightened it? Does anyone have a part number for the Toyota gasket? Dads426 do you have a part number for the copper/o-ring gasket?

Actually if it fits Saturn made one of the best seals made.we used them a lot on cars at work that had the same size drain.When we were getting them they were like 2 bucks each for the plug and gasket.Its a 2 part setup.Metal and a silicone type seal.Rocky

Mopars current replacement drain plug is a rubber coated steel plug that works very well