Broken oil drain plug and oil pan.

[Superfly_M3]

So I took my car to the dealer (voluntary oil change - its been 8,000km on that oil). I come to pick up my car late afternoon and the SA tell me there is a problem. When the mechanic took out the drain plug, he stripped the threads on both the plug and the oil pan. I asked if this was a common occurance, he said "We've seen a few". My car has had one oil change (after break-in) and it was done at the same dealer.

New oil pan and plug on route from Vancouver.

Has anyone heard of this?

[THE TECH]

How do you strip threads taking the plug OUT? Seems like this dealer needs some new "techs".

[Superfly_M3]

dunno, it baffles me as well

[the_works]

I can see them crossthreading the plug when reinstalling but not by removing the drain plug unless it was seized up.

[m3an]

yes, its acutally quite easy. I believe the plugs are a terrible design and actually used to use a bolt on my e46. I think the plug is actually a softer (aluminum ?) that allows it to strip first before damaging the pan. That being said, it shouldn't happen if care is taken; if the dealer is the only one changing the oil, they shouldn't be torquing that plug down so tight.

[THE TECH]

Originally Posted by talontid

yes, its acutally quite easy. I believe the plugs are a terrible design and actually used to use a bolt on my e46. I think the plug is actually a softer (aluminum ?) that allows it to strip first before damaging the pan. That being said, it shouldn't happen if care is taken; if the dealer is the only one changing the oil, they shouldn't be torquing that plug down so tight.

None of that explains why the plug would strip coming OUT. Going IN, definitely possible.

[m3an]

Originally Posted by THE TECH

None of that explains why the plug would strip coming OUT. Going IN, definitely possible.

well that's what the "dealer said" ... do you believe them?? Nothing strips coming out, only in. My guess.. they were hammering down on it putting it in and this happened. Of course they're gonna say it happened upon removal, it limits the liability; not, "hey we tightened it and broke it" C'mon, interpret the OP's post as you see fit.

[Stainless 45]

These days they use air ratchets for everything- too lazy to grab a torque wrench. Bolt was probably stripped when it was put back on after the last oil change.

[Superfly_M3]

Thanks for all the replies, here's my take.

I haven't seen the bolt (yet), and I don't know what material it is made from. My best guess is that the bolt and the oil pan are both aluminum; when you get two of the same metals, they contact and expand equally, hence no problems with leakage due to thermal expansion.

I've asked my dealer to show me the drain plug, I can even ask for the oil pan (don't really know how much I can see of the stripped thread). I'll try to get some more information as to why this thing broke, and will keep you guys informed. I really hope this is a freak accident due to use of a compressor and an airgun. Hopefully, BMW's drain plugs are not that weak to strip after 3 cycles.

To the guys using e46's drain plugs ... aren't you concerned about using different metals together to hold a fluid?

[BMRLVR]

Originally Posted by THE TECH

None of that explains why the plug would strip coming OUT. Going IN, definitely possible.

If it was put in cross threaded it could pull the threads out of the pan on the way out. You are right though, should be impossible to strip threads on the way out if the plug was installed properly....... I'd bet the damage was done on the last service!

I change my own oil on my M3 every ~8000KM (5000Miles). The first time I changed the oil at ~10000KM I had to use an easy out on the plug in the rear sump because the dealer put it in so tight after the break in service that the allen head socket stripped out the plug.

I don't understand for the life of me why people like to put such small fasteners so tight.

[01'325rip]

Happen to me about 2 months ago. Car was drinking a ton of oil ask them to look into it.

They claim the oil drain plug was stripped and needed a new one. Your not they only ones whos gone through this.

I think your right TECH it doesnt make sense for it to happen pulling it out they had to have done it placing it in.

[kitw]

I bet someone took an air impact wrench to the drain plug set the wrong way and tightened instead of loosened. It happens. Just make sure they replace the pan instead of retapping and giving you a bigger (non-standard) drain plug

[Malek@MRF]

Originally Posted by THE TECH

None of that explains why the plug would strip coming OUT. Going IN, definitely possible.

I think he meant the hex pattern where the tool goes in is stripped, not the actual threads. That's my guess. If its the actual threads that are stripped, then this damage probably occurred during the last service when the plug was being reinstalled.

A fastener can strip on its way out if it was put in incorrectly, or if there was a significant amount of debris on the threads.

[Superfly_M3]

The dealer said "they couldn't heli coil it" so I'm assuming the hex stripped.

[kiloil]

Originally Posted by Superfly_M3

So I took my car to the dealer (voluntary oil change - its been 8,000km on that oil). I come to pick up my car late afternoon and the SA tell me there is a problem. When the mechanic took out the drain plug, he stripped the threads on both the plug and the oil pan. I asked if this was a common occurance, he said "We've seen a few". My car has had one oil change (after break-in) and it was done at the same dealer.

New oil pan and plug on route from Vancouver.

Has anyone heard of this?

You sure they didn't use the oil bolt stripping for something they may have done but using that as an excuse?

[treadwellpar]

I believe the plugs are a terrible design and actually used to use a bolt on my e46

[kwike92]

It's hard to say what could of really happened... I worked As a tech for ford and the only time I have EVER seen a drain plug or oil pan thread strip, was when the tech was not paying attention and cross threaded it, or over tightened. The worst and most stupid thing I have ever seen was a "tech" putting a 3/8 air ratchet on the drain plug to tighten it... Obviously the this stripped the pan... Anyway, I don't think it's common for these things to happen I just think it was lack of experience on the techs behalf or lack of attention while changing the oil...

Just my $.02

[surlynkid]

it's called using an impact instead of hand tools. to remove the transfer case plugs on my truck, it specifically is stamped on the transfer case housing to not use an impact to REMOVE or install the plugs.

[m3an]

Originally Posted by kwike92

It's hard to say what could of really happened... I worked As a tech for ford and the only time I have EVER seen a drain plug or oil pan thread strip, was when the tech was not paying attention and cross threaded it, or over tightened. The worst and most stupid thing I have ever seen was a "tech" putting a 3/8 air ratchet on the drain plug to tighten it... Obviously the this stripped the pan... Anyway, I don't think it's common for these things to happen I just think it was lack of experience on the techs behalf or lack of attention while changing the oil...

Just my $.02

totally diff design on this car.

[BMRLVR]

Originally Posted by kwike92

It's hard to say what could of really happened... I worked As a tech for ford and the only time I have EVER seen a drain plug or oil pan thread strip, was when the tech was not paying attention and cross threaded it, or over tightened. The worst and most stupid thing I have ever seen was a "tech" putting a 3/8 air ratchet on the drain plug to tighten it... Obviously the this stripped the pan... Anyway, I don't think it's common for these things to happen I just think it was lack of experience on the techs behalf or lack of attention while changing the oil...

Just my $.02

I am not sure how it is in the US but up here in Canada you have to do an apprenticeship and get a licence from the Government to be a Mechanic, I had to go to school four times for two months each session, and put in four years on the job to get my licence as a mechanic. There should be no tech working on a car with a lack of experience. I guess one exception would be letting new apprentices perform lube services, which is quite common. Even then however, they should be under direct supervision from a journeyman at all times. Strip a plug and ruin an oil pan once and it may be no big deal, but I am sure if a tech or apprentice does this a second time he will be looking for a new job...... The oil pan lists at ~$975 dollars and the gasket is ~$40....... that is almost a weeks pay for a most techs and I don't think the dealer will foot the bill for that too many times.

[Groundpilot]

Thats why i hate taking the car to the dealer. Even for a simple thing like an oil change. But when i take it in, i always ask my SA to put an experienced tech om my car. They usually respond ''ofcource, if you prefer so''. That tells me that they let their novice techs to do the ''simple'' job like an oil change.

[kwike92]

Originally Posted by talontid

totally diff design on this car.

Your probably right. I have never personally changed the oil on my m3.