Options for over-tightened or cross-threaded oil drain plug

[7come11]

Well, for the first time ever I have apparently over-tightened or cross-threaded the oil drain plug after changing the oil. The plug will not tighten all the way and it does leak. What are my options? I'd better go get another 8 quarts of oil anyway! Thanks.

[haynes740]

Well, for the first time ever I have apparently over-tightened or cross-threaded the oil drain plug after changing the oil. The plug will not tighten all the way and it does leak. What are my options? I'd better go get another 8 quarts of oil anyway! Thanks.

Most likely removal of the pan for either rethread or replacement. That’s what I would do.


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[ConvGeorge]

Most likely removal of the pan for either rethread or replacement. That’s what I would do.


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Luckily the lower portion comes off fairly easily.

[clarkitect]

+1.

You could try chasing the threads with something or maybe a helicoil, but for all that effort might as well just replace the pan. Plus you can check for bits of guide!

- - - Updated - - -

Luckily the lower portion comes off fairly easily.

Upper pan comes off easy too once you get the engine out of the car!

[7come11]

Thanks. So oil pan, gasket and 25 fasteners, right. Is it just off and on? what about that oil levelling sensor...does that come into play?

[clarkitect]

Honestly I reuse the fasteners. Level sensor has to come off, it has an o-ring you can replace.

[SilverIris]

Cheapest OE BMW pan I saw on ebay is $50 plus shipping from PA. Off-brand ones are around $35, but might take longer to reach you. If you can source one for less or get it quicker, do it. Just swap over your oil level sensor if need be. Don't forget it has a gasket too.

In situations like this, be ready for the plan to go sideways. Been through it with my transmission pan and one bolt that decided to strip. Cut the pan's outer lip and got some vise grips on the bolt head. ALL of the old hardware went right into the trash, replaced with regular hex head stainless bolts. Pan needed the lip bent outward around each bolt hole to fit a regular 10mm socket.

Of course, cutting the lip and bending the lip to get vise grips on the stripped bolt head skewed the pan's mating surface a bit. Some oldschool metalworking got it straight, flat and true again. Just to be certain, I planished the entire flange area flat so there's no doubt about it. Stock style gasket that came with my transmission filter kit failed instantly, so I made my own reuseable gasket. It's thicker than stock, has more "give" to seal any imperfections I could have missed and held all of the bolts in place during reinstall because I made the bolt holes slightly smaller than stock. Reinstalled and absolutely zero leaks.

If you do this, remember to use anti-seize on your hardware. Otherwise, the softer aluminum threads in the upper pan stand the risk of galling against the harder stainless steel bolts (dissimilar metals). Pretty sure you don't want to replace that too...

[haynes740]

Thanks. So oil pan, gasket and 25 fasteners, right. Is it just off and on? what about that oil levelling sensor...does that come into play?

Do this job like you don’t want to see it again for a few years. I Learned a while back to replace eeverything and especially fasteners.


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[nmlss2006]

I'd strongly consider putting a helicoil in there. I did it on an E30.

Yes, if you can find a clean, straight pan with no corrosion for $50 or so you could go either way. M20 and M/S5x pans are a lot more money, for obvious reasons.

[kouks]

If you have a Junk Yard nearby go find one in an M62 on an e38 or e39 or first generation X5. Probably $5. Make sure they drained the oil first, check to make sure the drain plug is not stripped/crossthreaded/etc, then loosen the bolts with a 10mm socket or wrench, then use a cordless drill and take the bolts off. You can reuse your bolts. I've done several chain guide jobs and reused the bolts with no issue. I also use the technique of cleaning the metal surfaces with a degreaser, then apply a very thin layer of gasket maker, a new clean gasket, and tighten to 10Nm.

[subzero32]

Just use this as an excuse to put on a new pan. It will take about an hour taking your time.

[jclausen]

Install the new lower pan I don't think there's enough meat on the thing for a helicoil

[MrChrysler]

First make sure: Usually a drain plug uses much softer material than the oil pan, and therefore its the thread on the plug itself that gets damaged. I did it once on my e38, the thread on the plug flattened out as I have over-tightened it. After installing a new plug its fine.

2nd option you have is: You can use a dowty washer with an o-ring squashed inside. Put the washer on a drain plug instead off copper washer, insert thick o-ring that would fit in the gap. Something like this:

Dowty washer.png

3rd option you have is to remove the oil pan re-thread or replace it. If you go with that check the oil pump chain slack and check if the bolts are loose. Make sure that you have a new gasket. Old one wont be reusable.

[7come11]

I guess I got lucky. Owing to the softer material, only the threads on the drain plug were stripped. It was a bear getting the old one out , but I was able to insert a new plug and Crush Washer. All ok. Thanks for all the suggestions and advise. The collective experience on this forumis priceless.

[282hp]

Well heck's bells, I just did the same thing!
Is it super easy to strip the thread?? Or maybe I'm just super klutzy.

Anyway, I just did the first oil change on my "new" E38. (new to me, since I've driven it less than 500 miles)
When I put the plug back, I tightened it manually with a ratchet. I didn't go crazy, just turned till it felt good and tight to me.
But I saw the info that says the plug should be torqued to 18 ft/lb. I didn't have a torque wrench with that low range. So yesterday I went and purchased a torgue wrench for 5lbs-90lbs range.
Came back home, set the torque, and slid under the car, started turning the wrench and uggh, right away it felt looser instead of hearing a clicking sound from the wrench..........and now little tiny drops of fresh new oil seep out onto the flat side of the bolt head.
So I guess I had already tightened it past 18 ft/lb when I used a regular wrench on it? and that's why I couldn't get a click from the torque wrench?
I so hope it's just the bolt that's screwed up, and not the pan thread.

Do I need to fix this right away? if I drive around is it going to vibrate the bolt loose where I'll be leaving a stream of oil down the street?

[kouks]

Yes, easy to strip, and most likely was over-torqued plenty of times before, don't kick yourself about it.

My technique is to tighten until it feels snug (technical term), not tight, then add about 1/8 turn more. A new copper crush ring will always help it seal better.

My opinion is that it won't fly off while driving, unless you hammer down on the gas and put high pressure on the crankcase. But at the same time, why risk it, just get it fixed. I think the best way to "fix" it is to go get a used pan from a junkyard dog if there's one nearby. As long as it not stripped also. Otherwise you can do what was mentioned above.

[chemmech]

maybe the crush washers being sent out aren't annealed properly or takes too much to crush them with older threads? I just decided to use the vacula fluid extractor from now on (they no longer make these I believe it's mighty vac that has these as well as some other companies) it removes all the oil leaves very little in the drain pan there are other brands also, the last oil leak I had turned out to be from the crush washer not being tight enough then I re-tightened it and yep I don't think it was annealed right ie. material was too hard, a blow torch would be enough to anneal it though .....

[CPHES]

If you are stuck - there is an expandable rubber stopper style available at autozone. It works. At least until you get a new pan. I had an old Ford wagon, imagine my surprise when changing oil for the first time. It never leaked from there.....

[282hp]

I tried to put the old bolt back in this evening. It still looks ok.
The first few turns went smoothly, but then it was a dead stop. So obviously the thread on the pan is screwed up.

[282hp]

https://www.amazon.com/Bapmic-111317...4907799&sr=8-4

Look at this. I have located a bright, shiny new oil pan on Amazon, for only $37.95.
What do you think? If I get this, am I flirting with disaster?

I also browsed a few on Ebay, but most looked like they had been beaten into submission.

[CPHES]

It’s an oil pan - how bad could it be. No moving parts, no electronics. I’d try it.