BMW warranty denied because of over-rev on a DCT?

[gabeo]

Update 2: BMW NA came back and said they'd only pay for 50% for parts and labor. Without letting me even respond, dealer offered to eat the other half. This is on top of the free labor they did to get to the lifters. I'm quite appreciative for that, but I feel that it's complete BS that BMW used 200rpms of over rev go weasel their way out of paying for a fairly common noise issue.

Update: June 4, 2021
They found no issues with the lifters. They reassembled and re-torqued everything to spec and the noise is gone. They said this is not the first time they've see this being the case. They have submitted it to BMW NA for warranty approval but do not yet know if they will cover it. They also had to replace 3 injectors that broke upon removal (which they warned me could happen before hand). Waiting to hear back, hopefully later today. They all seem to expect them to cover it, but we will see. The one person I spoke with is also unsure if BMW will give me a hassle in the future, if I have issues, being that an over-rev is on the record for this car.

Original Post:
Hey All,

My new-to-me 2018 M3 Comp has the below sound, which it seems I'm not the only one. Took it to my usual dealer, and after pulling the data, BMWNA said I over-rev'd to 7800 RPMs and are giving me a hard time about repairs. They said they will not pay to replace the engine if it's a bottom end rod knock, which is fine, and I actually didn't want that. But after taking it to another dealer who seems to be more interested in helping (they offered to remove valve covers and do diag for free, regardless of warranty), they have started diving deeper into it and found it's coming from the top end, possibly lifters. They took it apart and found cams looked ok but they need to dig more to check lifters and such. They are confident that even if the lifters are ok, just taking it apart and putting it back together with proper torque will get rid of the sound (which I've heard of fixing it with others who have this noise). However, the BMW NA rep they're working with has so far not been willing to tell them if they would or would not cover repairs of top end stuff, until it's determined definitively what is causing the noise. So the dealer needed me to OK further diag, warning that worst case, I'll be on the hook for some of this, since the time they've put into it already is starting to add up and they can't keep going unless I'm aware of what it might cost if BMW NA denies us again.

Anyone hear of 200 rpms of over-rev on a DCT causing warranty issues? I don't beat on this car but I do have fun with it occasionally. Was a little surprised it was able to go past the redline. I get that they feel the right to deny me because of it, but I don't understand why they have to be difficult and couldn't just tell us,"yes we will cover these things since it couldn't have been caused by the over rev, but we will not cover these things because it could have be caused by it."

The worst part is I noticed the noise about two weeks after I bought it, long before BMW NA says the over rev occurred (based on the mileage it was logged), so I know I didn't cause it.

[wsccsw13]

The S55 is rev limited by the ECU. No hard stop on rpms like a governor, instead it pulls timing, cuts injectors, etc to reduce the chance of an over rev. The system is predictive and engine acceleration varies based on the gear you’re in, thus there are situations it can happen on both DCT and MT cars (ie without a money shift). Based on this method, it is still possible to exceed 7600 rpms but the ECU will record gear, throttle position, etc so you would be able to determine if you were ‘bouncing off the limiter’ so to speak. If that’s the case, as it should be on a DCT, then it’s not your fault. You may have to escalate it with BMW NA and/or get a lawyer to fight for your data. One final note, some tunes increase the rev limiter to 7800. If that’s the case, you’re out of luck.

[TopJimmy]

As long as you were stock and are still stock then I'd have the friendly dealership work the case through.

Being really nice helps them stay on your side.

[Wanted_M]

Sounds like a valve train issue to me but have the dealer show you the diag screen and when the in question over rev happened. Do you recall any situation in manual mode where your rpm's might have over revved as a spike?
This type of event could easily happen in first or second gear under full acceleration with loss of traction with DSC off. Good luck and I hope you get it resolved as warranty doesn't cover misuse or abuse of drive train even if its an unintended one time error.

[White340]

It's crazy they can give you limited info and try to deny warranty coverage ex ante. I would think that if they claim you overreved then they should tell you how that happened given that it's an auto with a limiter. If as mentioned above it was in certain situations that you can overrev then they should tell you which one of those situations was most plausible.

[gabeo]

Thanks for the replies. Car is all stock. The dealer is definitely doing what they can as far as I can see. It seems that the issue is BMW NA themselves. The service director at the dealer did seem to indicate it was an issue of bouncing into the limiter when in manual mode. They said that it's still possible to over rev in that scenario on the DCT. I've always known of money shifting and those who tune to increase the limiter, but neither of those happened obviously, so being given a hard time about it on a DCT is new to me.

[MisterF80M3]

Didn't you have an engine replaced with the same issue?

I thought this idle ticking is normal?

[SYT_Shadow]

Originally Posted by gabeo

Thanks for the replies. Car is all stock. The dealer is definitely doing what they can as far as I can see. It seems that the issue is BMW NA themselves. The service director at the dealer did seem to indicate it was an issue of bouncing into the limiter when in manual mode. They said that it's still possible to over rev in that scenario on the DCT. I've always known of money shifting and those who tune to increase the limiter, but neither of those happened obviously, so being given a hard time about it on a DCT is new to me.

If in manual mode it is possible to overev and damage the engine then BMW should be held responsible anyway.

Take a deep breath, if the car is stock they will cover it

[Morgen Black]

Here is more info that may help you if you do some reading and go prepared back to the dealer. I had my vehicle at BMW of El Cajon and they did a fantastic job correcting my vehicle.

I have first hand knowledge with my 2018 F80 at the dealer for four weeks. My F80 only had 17k+ miles on it when the noise appeared. The had to open a PuMA case and my car received plenty of new parts under warranty. My 2018 M3 had a noisy lifter in cylinder 1, was the final conclusion by the service foreman. They isolated each cylinder and found the noise only occurred when cylinder 1 was operating. They replaced both VANOS units, lifters and rocker arms, reinstalled the exhaust camshaft and intermediate shafts, set timing and buttoned it up. My car sounded like a tractor and now it is whisper quiet. All the info is in the thread below.

https://f80.bimmerpost.com/forums/sh....php?t=1645060

MB

[jpy1980]

sounds normal to me, change to a 5w-40 weight oil and that noise will go away.

[gabeo]

I did. Was hoping all these years later they'd have a more definitive fix rather than just throwing the baby out with the bathtub.

Originally Posted by MisterF80M3

Didn't you have an engine replaced with the same issue?

I thought this idle ticking is normal?

[gabeo]

I agree with this fully, but BMW NA doesn't feel that way. "It's still possible to over rev on a DCT, and damage from that is not covered."

The only proof I have is that I made the service appointment before the mileage at which the over rev happened. Though there could have been additional over revs that they saw earlier and didn't tell me.

Originally Posted by SYT_Shadow

If in manual mode it is possible to overev and damage the engine then BMW should be held responsible anyway.

Take a deep breath, if the car is stock they will cover it

[gabeo]

I heard this fixes it for some too. M3 manual also states: SAE 5W-30, SAE 0W-40 or SAE 5W-40 can be used.

The only thing about this is that a lot of the folks with this sound say it's only when cold and that it goes away. My noise never goes away, which made me think it was more worrisome and that a heavier oil wouldn't be enough.

Originally Posted by jpy1980

sounds normal to me, change to a 5w-40 weight oil and that noise will go away.

[Morgen Black]

My lifter ticking never went away after the engine was warmed up, and the senior mechanic at my dealership agreed it was not the normal sound you hear from an S55. After it was repaired, my engine is much quieter and the ticking sound is ever-so slight after warmup. I hope this gets all sorted out, good luck.

MB

[jpy1980]

Originally Posted by gabeo

I heard this fixes it for some too. M3 manual also states: SAE 5W-30, SAE 0W-40 or SAE 5W-40 can be used.

The only thing about this is that a lot of the folks with this sound say it's only when cold and that it goes away. My noise never goes away, which made me think it was more worrisome and that a heavier oil wouldn't be enough.

Try using Risoline engine additive. I used that and it helped.

[N1rve]

I had something similar on my last car and it was rocker arms. That sound doesn't seem familiar on my 2019 F82.

Though... I have a feeling your M4 was tuned from the previous owner.

[gabeo]

Update on original post

[gabeo]

Updated again in original post

[BPMSport]

If the car had bone stock software and is DCT, it would be absolutely absurd to deny coverage for an over-rev. Especially on a DCT… they would have no one to blame for that but their own software!

For example, although E9x M3s have an 8,400 RPM redline, the actual limiter in the software is 8,300. Boundary conditions/buffers and configuration for RPM "gradient" exist, and even with these it's not uncommon to see 8,500 in certain circumstances.

Even with a manual, unless there was a mechanical mis shift, warranty denial is ridiculous. The RPM gradient tells the biggest story. Good luck with your claim!

[gabeo]

Yep, fully agree! Car DCT/Engine software is fully stock, and BMW confirmed that. There was an "engine tuning" flag in there, but they told me that was from coding the mirrors to fold etc. They said despite that flag, the DME was fully stock, and that it was only because of the over-rev, that they were giving me trouble in covering things. Completely ridiculous. They said it can be done on a DCT if you leave it in 1st in manual mode and bang into the rev limiter, or if you have the traction control full off and floor it. Cannot confirm or deny that either of those things happened...

Originally Posted by BPMSport

If the car had bone stock software and is DCT, it would be absolutely absurd to deny coverage for an over-rev. Especially on a DCT… they would have no one to blame for that but their own software!

For example, although E9x M3s have an 8,400 RPM redline, the actual limiter in the software is 8,300. Boundary conditions/buffers and configuration for RPM "gradient" exist, and even with these it's not uncommon to see 8,500 in certain circumstances.

Even with a manual, unless there was a mechanical mis shift, warranty denial is ridiculous. The RPM gradient tells the biggest story. Good luck with your claim!

[BPMSport]

Originally Posted by gabeo

Yep, fully agree! Car DCT/Engine software is fully stock, and BMW confirmed that. There was an "engine tuning" flag in there, but they told me that was from coding the mirrors to fold etc. They said despite that flag, the DME was fully stock, and that it was only because of the over-rev, that they were giving me trouble in covering things. Completely ridiculous. They said it can be done on a DCT if you leave it in 1st in manual mode and bang into the rev limiter, or if you have the traction control full off and floor it. Cannot confirm or deny that either of those things happened...

That is why the rev limiter gradient calculations exist. Usually the higher rpm action is not in first because the ecu sees the rate of change and buffers earlier. Their approach is really unfortunate.