Original Oil Drain Plug Washer Material

[JohnGunn]

I've, finally, replaced my much loved and respected 183,000 mile 1990 Festiva L with a 79,000 mile 1994 Aspire.

As soon as I finish going over it, I promise to give a full report of the whole process, but, until then, I have some questions, small and large, which I need help in addressing. I've ordered the Service Manual and the Electrical/Vacuum Manual from an eBay seller, but they haven't arrived yet.

First question: What was the material used in the oil drain plug sealing washer as delivered from the factory? My guess would be copper, but I want to start out doing the best I can for this car.

Other questions will be asked in short individual posts.

Thanks for any help.

John Gunn
Coronado, CA

[WmWatt]

On my '89 it was copper. It got lost. It's since been replaced with nylon. I thought it was leaking but it's probably the pan gasket which is leaking. Oil drain plugs are a standard generic item at auto parts stores.

[Nerd Racing]

in a pinch you can use some RTV sealer if you clean up the area really well.

[TominMO]

I use whatever washer is on there, and put high-temp grease on the threads. Never have a leak.

[AlaskaFestivaGuy]

I always use copper. It crushes just right so the plug won't leak and won't work its way out (if torqued properly). Airplanes use copper washers extensively for the same reason, even on the spark plugs (two plugs per cylinder, on separate ignition systems).

[drddan]

Nylon will work, as well as delrin, teflon, nylatron, copper...
Dont use aluminum, steel, or rubber.

[JohnGunn]

Based on the input to this thread, I chose to buy some copper washers at AutoZone to use on my new Aspire. I used one of them to install a quick change system that I found at Harbor Freight. When I discovered that my engine needed serious internal cleaning, I removed that system because the flow rate through it was little more than a trickle. I ordered a Fumoto Oil Drain Valve which came with a blue washer, which appears to be fiber, glued in place.

But since I am interested in getting as much of the old oil out of the engine to speed my cleaning efforts, I decided to go back to using the original drain plug. Since the copper washer I had used only once before looked OK, I decided to use it again. That was a mistake. Once the copper has been compressed, it gets hard and refuses to be compressed a second time. When using a torque wrench it gets to a point where all movement of the wrench suddenly stops. As the torque continues to rise nothing moves. Without that feeling of increasing resistance as the wrench turns, I get a very uncomfortable feeling that there is not much tension holding the plug in place.

In addition to the hard, unyielding feel as I tighten a copper washer, the thing leaked. I tried to tighten it some, but it remained hard and resistant. In the end I resorted to loosening the plug enough to put some Permatex Ultra Copper RTV on both sides of the washer. In spite of the fact that oil was leaking down as I shoved it into the space, once tightened it did stop the leak. No more copper washers for me.

In the past I had good luck using the same nylon washer for time after time, and every time I got a nice feeling that as I turned the plug tighter there was a resistance built up that would keep it tightly in place. I didn't use a torque wrench and it never leaked. Or if it did, I had only to turn it a little tighter for it to seal. Until I install the Fumoto valve I'll buy a nylon washer and use it until my engine cleaning procedure is completed.

[TominMO]

Again, grease on the threads. No leaks.