[potato1337]

Around 2 months ago I had my 2020 M2 Competition DCT serviced at BMW dealership (at around 47.5k km). They've done a standard oil change, air filters, and spark plugs. Today after ~7k km I decided to change the oil (the car is still under warranty and has an active service plan but 24k km interval for oil is just insane so I change it every 6-8k). Surprisingly, I found small pieces of metal in the oil filter. When removing the drain plug I found out that it had some unknown substance on the bolt head + some on the actual thread (I've previously changed oil on my own and it never was there). On top of that, there was no washer that is supposed to get replaced with each oil change...

I think they stripped the bold/thread, put a shit ton of silicone on it, and called it a day... not a word to me about it. After closer inspection, part of the oil pan thread is gone and parts of it came out with the oil...

View post on imgur.com

My questions are:
1. Is using silicone a standard BMW procedure for fixing stripped oil pan thread? It sounds insane but I am not a mechanic. Also, the fact that they haven't even mentioned it makes me furious...
2. Considering the fact that the source of the metal parts in the oil is the oil pan thread and before the oil goes to the engine it has to go through the oil filters, what are the chances that this could've damaged the engine?
3. I haven't talked to the dealer yet because they're closed at this time but if they admit fault, and replace the oil pan, what should be done to ensure no damage was done to the engine? Before today's oil change, the car was running fine, however, how do I make sure there are no scratches on the engine internals (cylinders, bearings, etc. what else?) that are going to reduce the life of the engine?

[F87source]

Originally Posted by potato1337

Around 2 months ago I had my 2020 M2 Competition DCT serviced at BMW dealership (at around 47.5k km). They've done a standard oil change, air filters, and spark plugs. Today after ~7k km I decided to change the oil (the car is still under warranty and has an active service plan but 24k km interval for oil is just insane so I change it every 6-8k). Surprisingly, I found small pieces of metal in the oil filter. When removing the drain plug I found out that it had some unknown substance on the bolt head + some on the actual thread (I've previously changed oil on my own and it never was there). On top of that, there was no washer that is supposed to get replaced with each oil change...

I think they stripped the bold/thread, put a shit ton of silicone on it, and called it a day... not a word to me about it. After closer inspection, part of the oil pan thread is gone and parts of it came out with the oil...

View post on imgur.com

My questions are:
1. Is using silicone a standard BMW procedure for fixing stripped oil pan thread? It sounds insane but I am not a mechanic. Also, the fact that they haven't even mentioned it makes me furious...
2. Considering the fact that the source of the metal parts in the oil is the oil pan thread and before the oil goes to the engine it has to go through the oil filters, what are the chances that this could've damaged the engine?
3. I haven't talked to the dealer yet because they're closed at this time but if they admit fault, and replace the oil pan, what should be done to ensure no damage was done to the engine? Before today's oil change, the car was running fine, however, how do I make sure there are no scratches on the engine internals (cylinders, bearings, etc. what else?) that are going to reduce the life of the engine?

Yikes that is unfortunate to hear, and if you are still under warranty I would try to get the entire sump replaced under warranty. If you can't get it replaced, then don't fret I have helped TONS of people repair the oil pan threads before so I have no doubt I can help you get it fixed properly.

OK now let me answer your questions first:

1). Absolutely not, your dealership is absolutely moronic for using silicone to fix the stripped threads, this is the most botched half-a**ed "fix" I have ever seen (sorry for the harsh language, but it pisses me off seeing dealerships do this crap). Especially on the oil drain plug - because if that thing leaks your engine could be starved of oil. The real fix should have been a thread repair - a helicoil, or a replacement oil pan.

2) No your engine should have been fine, the oil pick up screen and the oil filter should have stopped any particles from hitting the engine. I'm worried about your oil pump though.

3) There's probably nothing you can do to check the engine, maybe used oil analysis to check for wear, check the oil pick up screen, but honestly aside from that there isn't much you can do without tearing apart the engine. I honestly think you'll be absolutely fine though, because the metallic fragments from a stripped thread are huge so the filter will have absolutely no trouble catching all of it. I would however flush the oil a few times (regardless if your shop replaces the sump or if you have to do a thread repair - which I will discuss below, however if you do a thread repair you'll have to flush it alot) to ensure everything is out of the loop going to the oil filter.


Now how do you do a thread repair? Well I would use a helicoil over a timesert of tapping the threads larger for the reasons I discuss in this post:

https://f80.bimmerpost.com/forums/sh...0&postcount=46


Essentially helicoils take out less material to be installed vs. a timesert or tapping to a larger thread, this will make the probability of success higher because the side walls of the drain hole is very thin. BMW also mentions in ISTA (their shop manual) to use helicoils for other thread repairs, they never mention tapping the hole larger or using a timesert. So even BMW themselves seem to prefer helicoils.

Anyways if you have to go this route let me know and I will guide you through it step by step so you do it right.

[Track/S]

The copper gasket is glued to the oil pan, everything is fine, don't give it so many turns, the metallic remains seem to be from the oil pan thread.

[potato1337]

So to my surprise, the dealership admitted the fault (I was pretty sure they were going to blame it on anything but them since I didn't really have any proof that it was them - besides me knowing it was 100% them), apparently the mechanic that was working on it told the service advisor about the situation/documented it but the advisor for some reason decided not to tell me about it... The guy is no longer working there so it's impossible to get more info as to why (they wouldn't tell me if he was fired or not so I suspect it might've not been his first fuckup...).

The oil pan thread was repaired (

View post on imgur.com

), the oil pan was cleaned and new oil was put in. Additionally, I got them to write a statement describing the whole situation.

F87source Thank you for your detailed reply! According to the dealership, the parts of the thread were way too big/heavy to be able to be picked by the oil pump.

Track/S You're right, the copper gasket was glued/pressed into the oil pan. After the thread repair it's no longer there.

[F87source]

Originally Posted by potato1337

So to my surprise, the dealership admitted the fault (I was pretty sure they were going to blame it on anything but them since I didn't really have any proof that it was them - besides me knowing it was 100% them), apparently the mechanic that was working on it told the service advisor about the situation/documented it but the advisor for some reason decided not to tell me about it... The guy is no longer working there so it's impossible to get more info as to why (they wouldn't tell me if he was fired or not so I suspect it might've not been his first fuckup...).

The oil pan thread was repaired (

View post on imgur.com

), the oil pan was cleaned and new oil was put in. Additionally, I got them to write a statement describing the whole situation.

F87source Thank you for your detailed reply! According to the dealership, the parts of the thread were way too big/heavy to be able to be picked by the oil pump.

Track/S You're right, the copper gasket was glued/pressed into the oil pan. After the thread repair it's no longer there.

Glad to hear it was repaired and the dealer acknowledged their mistake and that you have it in paper - that is really important for future warranty claims, and it was nice of the dealer to accept fault (it sort of makes up for them trying to hide the issue, but not really).

Did you dealer tap a larger hole or did they use a helicoil? I can't really tell by the image.

[potato1337]

Originally Posted by F87source

Glad to hear it was repaired and the dealer acknowledged their mistake and that you have it in paper - that is really important for future warranty claims, and it was nice of the dealer to accept fault (it sort of makes up for them trying to hide the issue, but not really).

Did you dealer tap a larger hole or did they use a helicoil? I can't really tell by the image.

Larger hole and larger bolt.

[tropicatango]

Torque spec for the drain bolt is 20 n/m so around 15 ft/ lbs, it doesn’t take a lot to over tight it.

That’s why i like to do my own maintenance. No bad surprise

Good they admit and everything is back to perfect for you

[F87source]

Originally Posted by tropicatango

Torque spec for the drain bolt is 20 n/m so around 15 ft/ lbs, it doesn’t take a lot to over tight it.

That’s why i like to do my own maintenance. No bad surprise

Good they admit and everything is back to perfect for you

It's 25 nm, same as the oil filter housing

[tropicatango]

Originally Posted by F87source

It's 25 nm, same as the oil filter housing

Yeah you’re right, 25 nm is not a lot, that’s my point,

[F87source]

Originally Posted by tropicatango

Yeah you’re right, 25 nm is not a lot, that’s my point,

Yup, I agree. That's why you gotta be really careful.

[F87source]

Originally Posted by potato1337

Larger hole and larger bolt.

I see, do you know what the size of the new threads are?

I've only heard of a person tapping to a larger hole once or twice on this forum (but it's good to know this is a proven option too), and personally I would prefer a helicoil because it takes out the least amount of material.

[potato1337]

Originally Posted by F87source

I see, do you know what the size of the new threads are?

I don't, I will try not to forget and check that with the next oil change.

[potato1337]

So an update... ~4k km after a "fix" I started noticing little

View post on imgur.com

on my garage floor. Exactly in the same spots (relative to how the car was parked). I suspected right away where it was coming from but didn't have time to actually check.

Took it to another dealership to diagnose and:
1. The oil is indeed leaking out of the oil drain plug.
2. The oil pan is not repairable.
3. They're going to replace it, the dealership that fucked it in the first place is paying for it.

Will keep you updated...

[F87source]

Originally Posted by potato1337

So an update... ~4k km after a "fix" I started noticing little

View post on imgur.com

on my garage floor. Exactly in the same spots (relative to how the car was parked). I suspected right away where it was coming from but didn't have time to actually check.

Took it to another dealership to diagnose and:
1. The oil is indeed leaking out of the oil drain plug.
2. The oil pan is not repairable.
3. They're going to replace it, the dealership that fucked it in the first place is paying for it.

Will keep you updated...

Glad that original dealer will be paying, hopefully everything will be fixed soon.


Also, this is a reason why you shouldn't tap larger, there's always a chance the original O-ring won't be able to seal the new larger OD as well.

[E90convert]

If for some reason the dealer screws you again (they will find a way!), Time-Sert kits are used in the BMW TSB for drain plug thread repair. I used one on my X5 for the same problem. Easy to install and no leaks after the repair.

[F87source]

Originally Posted by E90convert

If for some reason the dealer screws you again (they will find a way!), Time-Sert kits are used in the BMW TSB for drain plug thread repair. I used one on my X5 for the same problem. Easy to install and no leaks after the repair.

So strangely enough, when I looked at the TSB bmw does mention a timesert is used - and the guide was updated to show info for a timesert, yet I found nothing in their guide about actually using a time sert - they only bored the hole bigger to M14: https://static.nhtsa.gov/odi/tsbs/20...61547-9999.pdf


I also wouldn't time sert it after already boring it larger for an upsized drain bolt, because there likely will not be enough material left in the side walls to survive tapping it even larger for a timesert.


IMO I think a helicoil (or similar kits - ez coil etc) is a better bet than a timsert. The reason why is because they take almost no material out of the side wall (which is pretty thin on these aluminium oil pans, and theres a huge notch already taken out of them for better oil draining which doesn't make these holes particularly strong) - for instance an m12 thread will only require the hole be bored out an additional 0.3 mm so 12.3 mm diameter. That is literally nothing at all, so the chance of the side walls crumbling or not being able to hold up to torquing down a bolt is very low. A time sert takes alot more material out, and also requires a chamfer be cut and the insert be hammered in - remember the hole is notched so if you cut a chamfer you must factor in how thick is the oil pan before you start reaching that notch - and now you are thinning the oil pan even further. This all makes the chance of success alot lower.

I'm not saying a time sert will not work (I have seen one or two successful attempts on the S55 pan before) but I am saying the best chance of success is a helicoil - and I have personally helped 10+ on this forum alone successfully repair their S55 oil pan threads, and am currently helping another individual right now as we speak.


Now this is the first time I have ever seen BMW recommend using a time sert, because in ISTA all the thread repairs are recommended to be done exclusively by aluminium helicoils - whether it be engine block threads or subframe threads (which consist of holes which also have really thin side walls).


Anyways heres an image of the S55 oil pan:



Not the thickest side walls ever but not as paper thin as the sub frame side walls or even the corner brace bracket side walls, but it is really soft aluminium so it is really not going to be strong if you make it thinner.