Quiet thunk/clunk noise when accelerating

[Tofipok]

Hello hello, relatively new owner of a 2015 I3 BEV here.

Recently I started hearing a quiet clunk type noise when accelerating after coming out of regen. This noise does not show up when accelerating from a standstill, just when the motor "switches polarities". The sound sometimes disappears for weeks, then comes back again.

I have in march got a new 12 volt battery in the car (original owner didnt change it since 2015), new brakes all around in january and I got new tyres last June, if that is important.

Hit me with all the worst news you have, if it's motor mount or not, I need to know.

[Arm]

Even if it is the motor mount, that's better news than a failing motor or gearbox. Motor mounts aren't that hard to replace.

[frictioncircle]

Welcome to the forum Tofipok...

Take your i3 to a BMW dealer and ask them for a "key read".

Just from having your key fob they can tell which service bulletins have been done to your car.

Then ask if your i3's motor mounts have been replaced under warranty. If not, nicely ask if BMW would extend "goodwill" coverage and replace them.

I've found BMW NA to be very helpful when outside of warranty.

[alohart]

Then ask if your i3's motor mounts have been replaced under warranty. If not, nicely ask if BMW would extend "goodwill" coverage and replace them.

I don't believe that the motor mounts on early U.S. i3's were replaced under warranty due to a service action. However, the bolt that attaches the motor mount bracket was replaced with a stronger bolt under warranty due to a service action on our 2014 i3 BEV. If the stronger bolt broke, BMW would authorize replacing the polymer motor mount bracket with an improved aluminum version which used an even stronger attachment bolt. This also required replacing the motor mounts because the original mounts weren't compatible with the aluminum bracket.

[frictioncircle]

Hello again, Tofipok –

I think this might address your driveline problem:

SI B22 01 15 – Engine and Gearbox Suspension, Left Side Engine Mount Broken

https://static.nhtsa.gov/odi/tsbs/2015/ ... 6-9999.pdf

[Tofipok]

Guess I should've mentioned this in the original post - I am in Denmark, and the car originally comes from the Netherlands (at least that's what I think, I got the KVL recall message in dutch)
I asked the dealer about a warranty related question before and they gave me a flat-out no, so sadly I don't think they would change my mounts out of their blessed hearts.

Thanks for the replies!

[frictioncircle]

Hello Tofipok –

A BMW publication that begins with "SI B" means "Service Information Bulletin" (SIB).

From my US perspective, any US BMW dealer will perform a SIB on any car regardless of warranty status.

You don't even need to bring your car to the dealer, just the key. Your dealer can read it and they will be able to tell all the SIBs performed (or not performed) on your i3.

And just to be more clear, a BMW SIB is, effectively, a worldwide "repair bulletin". Stop by your dealer with the above SIB number and they should do it for you.

[alohart]

A BMW publication that begins with "SI B" means "Service Information Bulletin" (SIB).

From my US perspective, any US BMW dealer will perform a SIB on any car regardless of warranty status.

I just took our 2019 U.S. BEV to our BMW dealer for a state safety inspection. It had the original November, 2018, system software which I wanted updated to the current version to fix an electric power steering bug that could cause a sporadic temporary loss of power steering. Several i3 owners have reported this problem but I had never experienced it. With the help of this forum, I was referred to SIB 32 11 19 Steering Assistance Sporadic Reduction: EPS Software Update Ext Ltd Wty Coverage that addresses this problem. It also extends limited warranty coverage for this software update to 10 years/120,000 miles which indicates that this software update would not be performed at no cost beyond 10 years/120,000 miles despite a SIB existing.

However, a scan of my fob did not identify this SIB as needing to be performed. It did identify SIB 84 09 22 Service Action: Programming the Telematics Control Unit - 3G Sunset. This Service Action requires updating the telematics control unit software to the current version. However, the software for all control units must be updated as a package (integration level) to keep everything working together correctly, so this would also fix the electric power steering software bug.

I wonder whether the phrase "Service Action" must be in a SIB title for it to be identified in a fob scan and thus performed automatically by a dealer. Even though the electric power steering SIB wasn't identified in a fob scan, I'm pretty certain that it would be performed on an i3 under warranty if an owner complained about a sporadic loss of power steering which I did. My Service Advisor asked my questions about the power steering suggesting that he was documenting my complaint to justify performing the fix.

My experience with our BMW dealer since buying our 2014 BEV new from them is that they don't update the system software to fix all bugs known to BMW as described in SIB's. They only do so when an owner complains about a problem that a system software update would fix while under warranty, if an SIB is a Service Action (e.g., replacing the defective KLE on our 2014 i3, replacing the weak motor mount bolt on our 2014 i3, fixing the telematics control unit on our 2019 i3), or if NHTSA has issued a recall to fix a problem (e.g., reprogramming the driver airbag on our 2014 i3).