I still have a small leakage from the Oil Drain Plug after changing oil/filter and
Drain Plug Gasket. I dont want to tighten it harder and destroy the threads in the oil pan. I would like to buy a new Drain Plug and Gasket first but I am not sure about the threads. Unfortunately I live in a mm-land. I would appreciate some help. Could it be 1/2"-20 (UNF)? Which Gasket seals best? Alu, copper or nylon?

 

1/2-20.

If the plug hole is worn out, they make oversized drain plugs for that purpose. Single and double oversize. I don't know what the actual size of those would be. Probably in the thousandths bigger.

Nylon is the best plug gasket IMO.

 

Thanks 351Cleveland C4!
I think the threads in the Oil Pan are ok. I will try to just order a new Plug with a Nylon Gasket.

 

I would bet both are sloppy and you would be best suited with an oversize plug and a sacrificial rubber washer.

 

mm-land?
Drain plug gaskets are easily available at any auto parts store or on-line. Fiber, nylon, rubber, compressible copper - take your pick.They all work pretty much the same the first time. I'll second that nylon ones work best for repeated tightenings for me.

 

You are probably going correctly. The one in my '76 460 is a 1/2"-20. I agree with the others about the gasket. The synthetics seem to seal better especially if the sealing surfaces are not perfect. The ones with the self washered (flanged) heads may work a bit better at sealing. Here are some to choose from.
Engine Oil Drain Oil Drain Plug Parts | RockAuto

 

Thanks! I wish we had your assortment "over here". I got an aluminum gasket
and torqued to spec but it was still leaking. Didn't want to tight it harder.
Now I ordered a new Drain Plug and Nylon Gasket ( they didn't had one in store) I will try this before I go on with an oversized.
HoustonDave! I am sorry about my "mm-land" expression. I just meant we mostly use the metric system over here and it's sometimes even difficult to get
the most common UNF/UNC bolts and nuts. Thanks for your helpfulness and
patience with my bad (very old) school english. I appreciate it A LOT ! ! !

 

my apologies for not noticing you were in Sweden - that explains a lot. Do a search in the forum; there are a LOT of internet and mail-order places which may increase your parts availability. Sadly, the shipping will probably be high as well, but an available expensive part is 'way better than an inexpensive non-available one.
http://www.engineeredpartsinc.com/pd...onversions.pdf says you should look for a M14 x 2 plug.

 

You know that the "oversize" plugs cut a larger diameter thread but with same thread pitch. Once used, that plug or one just like it is what will fit that new hole, a standard 1/2-20 will not work after that.

They are offered in at least +1, +2 .... and some places even have a +3 "oversize".
I'd start with just the +1 oversize so you have a backup plan three years from now.

 

The metric system is in many ways a superior system to the old USA way of doing it, and the USA is gradually changing, but to continue our old vehicle hobby we will have to use the old SAE method. Your English is very good and understandable. Some of the USA auto parts merchants will ship to most of the civilized parts of the world. It may require a bit more time to arrive in northern Sweden, but if time is not a factor, you might explore ordering from them. The one I sent has many choices on drain plugs and plug gaskets, which can be ordered separately. Their catalog is available in several languages and their prices can be shown in many of the world's currencies. If your local supply is difficult mail order might be better to get certain things.

 

I had a slow drip from the drain plug for years, tried copper and nylon washers and nothing stopped it. Always said one day I'd replace the pan (figured the pan was shot). This last oil change the plug finally stripped out and after replacing with a new one from Advance Auto Parts I haven't had a single drop of oil. The plug is bone dry now. I figure the threads on the old plug were worn out, allowing oil to seep out. Heard from a few buddies that the steel oil pans are made of pretty hard metal, so stripping them out is hard to do. Drain plugs are purposely made out of softer metal, to help seal and prevent stripping out the oil pan. Not sure if it's true, but makes sense!

 

Once again. Thanks a lot everyone!!
tbear853. Yes, I understand but I am going to try a new 1/2-20 Plug with a Nylon Gasket first and if it's not working I will try the +1 oversize. If I am going for the oversize Plug I will come back to you for some more questions about how to perform it.
Ozzie H. I am going to make an order from USA this winter and have been used NPD, Summit and some more auto parts merchants before. Time is not a factor. I also got some fantastic help with used parts and shipping from a forum member. Most of the time I prefer good used parts before chinese steel.
tlrtucker. Your theory about the Oil Pan sounds interesting. What I can se looking at the threads in the Pan they look quite normal but Plug looks worn.
I will hope for the best with the new one!

 

For sure ..... I would do the same. I have several I keep just hanging on nails in package to have if needed.

I also meant to add that lately I've been using oil drain plug gaskets that are like a O-ring captured in a metal washer. Very good results and no chance of a crack across the face. I have had nylon ones crack.

 

It's a very good suggestion with the O-ring/Metal Gasket. Dont find them in 1/2" over here but I will order a couple from USA if it's not working with the Nylon Gasket. My third choice is the oversize Plug. Even an easy-fix can be complicated on the wrong continent and above the Arctic Circle!!! Thanks a lot!!!!

 

My paternal great-grandparents immigrated from Sweden and settled in Montana. I guess Sweden wasn't cold enough. My great-grandfather liked to say Montana had 9 months of winter and three months of late fall!

More importantly, when I had a pan drain bolt drip, I replaced it with a standard size plug and washer. I think the plugs are softer than the pan threaded inserts, and eventually can leak