How would you repair a semi-stripped oil pan?

Big Wave D · Jul 18, 2011

Was changing the oil on my wife's 2005 Ford Freestyle. I was wiping off drain plug and immediately noticed something was wrong. About half the threads on the 'head' end of the drain plug were filled with the threads from the oil pan.

Pan is made from aluminum. The plug is made from steel. The plug has "metric" stamped on the head. There is ample material to work with.

As a little background, I am usually the one who changes the oil on this vehicle. The drain plug has always seemed overly tight/hard to take in and out. I don't use any kind of air tool to install drain plug, but I've never tightened an oil plug with a torque wrench either. This is first time on any vehicle I've owned or worked on that this has happened.

Some questions are:

1) If I just decide to drill out the old threads and cut new ones, do I want to make them fine or coarse thread?

2) Do I stay with a steel drain plug or get something made or brass or other metal?

3) What are thoughts about installing some kind of permanent drain valve like this and using JB weld of some form of epoxy to permanently affix it? It still has about half of the original threads left and using the JB Weld only on the end where the threads are gone.

I've attached some pictures. The one is what things looked like when the drain plug came out. The other is with the threads removed for comparison.

Thanks to any and all for ideas and suggestions.

wdchyd · Jul 18, 2011

Most Auto parts stores carry oversized drain plugs with matching taps for quick repairs.....

psj12 · Jul 18, 2011

I like the drain valve idea but I don't think I would glue it in. If the valve ever failed you couldn't remove it. Additionally they sell self tapping, oversized replacement plugs.

Western · Jul 18, 2011

Possibly a "helicoil" (sp) usually at an auto parts store too.

sld · Jul 18, 2011

Or weld a bung to the outside and use that for threads...inside would be better but outside would be much easier.

czechsonofagun · Jul 18, 2011

To answer your question I would drill it out and cut a fine thread in it in the next size and forgot about it.

Usually steel on aluminum is a bad juju, but this is an oil pan and there is plenty of oil around to keep it from rusting together.

My $0.02 only

wrenchturner · Jul 18, 2011

Let's not make this more complicated than it really is. Dorman makes over sized drain plugs with self tapping threads. Go to the auto parts store with your old plug to match then bring it home and screw it in. Remove plug and pour a couple of quarts of used oil through to wash the shavings away. Reinstall plug and new oil. Easy repair.

xtn · Jul 18, 2011

Don't know how you're going to fix the threads, but want to throw out a thumbs up for the Fumoto valve. I love mine.

Mace Canute · Jul 18, 2011

If you decide to drill it out and re-tap it, remember...it is quite important to have the plug at exactly 90 degrees to the pan's mating surface if the sealing is done by a washer. You likely will have only one kick at the can, eh?