MB/Tesla Motor replaced

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New member
Sep 12, 2018
Well, My 2014 B-Class is on its 3rd motor in only 40,000 miles.

1st motor replacement was caused by the motor being flooded by coolant fluid.
The interesting part is that the vehicle continued to run.
The only problem I noticed was a very slight hesitation when beginning to accelerate, otherwise no other issues.
I took my car in when the service immediately message appeared. After discovering the fluid in the motor, MB decided to replace it.

2nd motor was replaced after only 1500 miles for the same reason. MB still has no idea what is causing this problem.
MB currently has their engineers working on it.

Has anyone had any similar issues?


I have a 2014 B class too.
Replaced drive unit for the first time in March 15, 2018. Initial report states coolant in drive unit but the message was truncated. The fix was to replace the drive unit.

Second drive unit replaced October 3rd, 2018. This was an emergency replacement because the car shut down while we were driving. Luckily it did not occur on the freeway because the car went from moving to dead in less than 30 seconds. I was lucky enough to have just enough momentum to stop dead in a left turn lane at the intersection. Display had a red warning about malfunction and not to restart the car.
The warranty had just expired but MB was good enough to replace the DU on warranty.

I have no idea if the DU will go out on me again. I feel that this should be a recall and MB should replace or buy back the cars suffering multiple DU failures. It now makes me a little nervous to be driving on the freeway but this isn't exactly a disposable car.

Have you contacted MB about possible lemon law?
Barely had my car for a week and now I have the Malfunction Visit Workshop (10/10/2018) display again while driving up a hill on the way home.
Since I didn't want to go through a second abrupt stall in the freeway, I had the car towed to the dealership. Under diagnostics right now but I'm not optimistic that they actually resolved the problem.

It would be unbelievable if they had to replace the DU three times in the same year. Waiting to hear back.
This really sucks, pardon my language. Best of luck to you. You should get a free loaner and ask your insurance company what they are prepared to do if the car is a writeoff. Sorry to bring up this bad scenario. Obviously hope they fix it properly this time.
I filed a claim with BBB Autoline and contacted MB and after the initial response emailed the VP of Customer Service.
I'll update here once this is or isn't resolved.

Absolutely, march up the line at MB. You might want to include their head of North America which I think is in NJ. Sorry I don't have his contact info. There are two things wrong here (at least), first, they must stand behind all their cars, not some of their cars and second, faulty service on discontinued model.

FYI, here is what they did do for me back in 2003. I bought a new E500 with dealer installed navigation system but received a car without it while they said they were waiting for parts from Germany. OK. Six months later, my salesman called me to say that the option had to be installed only at the factory. He offered me the option money back OR A NEW CAR WITH FACTORY INSTALLED NAVIGATION. I turned in my car with 5K miles on it and received my new one, no money exchanged.

The moral of that story is that if they can't fix yours, they should locate and get you a new or relatively new 2017 with an intact warranty, if they can't fix yours.

Safety is the biggest concern for them as the motor crapping out on the highway is their nightmare scenario. One member's wife had the motor zonk out on the highway but safely pulled over. She was shaken. I had mine crap out going 30 mph in the city but was able to pull over. After considering my options, I decided to ignore the message and restarted the car and drove the 2 miles in the slow lane with blinkers on to the dealer. For me, it was the software gliche, not the motor.
Thanks for the advice. I'll do my best trying to march this up through the system and see if I can get some resolution. I have yet to hear back from MB. My last email was addressed to Christian Treiber, VP Customer Services.
If I gain no traction, then I'll contact Dietmar Exler, CEO.
Was contacted by Chris an Executive Referral Manager. He indicated that they would not replace my car but I could buy any available 2017 B class if I wanted to. They will take 4-6 weeks to review the car and if it qualifies will have a third party company appraise the car and make an offer to buyback if it qualifies.
He indicated that if the car was repaired, within this time frame, I could continue to drive it while they work out the buyback, if it qualifies. I reminded him that if the catastrophic failure where the car stalled out in the intersection was to happen on a freeway, the results could be very bad. He noted that he would place a note to the team to try to expedite but could not guarantee that it would happen.

Doesn't sound very promising.

I did file a complaint with the NHTSA.

I figure if others are facing similar issues, it would be good to get a recall set up if MB does not step up to the plate. It took four years for these issues to show up near the end of my warranty, and since the cars remain essentially the same through the 2017 models, we may expect to see others model years show the same issues as the end of their warranties come up. I hope not, for everyone else but best be prepared.

I think they can and will do better. Keep up the pressure and definitely let them know that you are aware of others having the same safety problem. Good luck.
The Tesla motor used in the B-Class ED / B250e is shared with the 2012-2014 Toyota RAV4 EV.

As the RAV4 fleet is older, the motor problems are well known. Leaking coolant is known that can enter the inverter and damage the electronics.

Bearings wearing out is known (with motor noise).

We have begun doing motor rebuilds and replacements for the RAV4 EV, and we will extend that service to the Mercedes.

Also, we will offer package deals to repair or replace the motor with a JdeMO fast charge kit.

Tony Williams
Quick Charge Power LLC
1780-104 La Costa Meadows Drive
San Marcos, California 92078 USA
[email protected]
Twitter: QCPower
1-760-798-0342 Office, M-F, 9-5 Pacific Time
Hi Tony, this is great information. I just bought a used 2014 B-Class electric with about 20,000 miles on it.

Do you have a rough idea of what mileage the drive train issues appear? I've heard 40,000.

And if you don't live in California, what are the options? Do you suppose some local mechanic could remove the motor, ship it to you for rebuild, then re-install? Or would that not be feasible, esp. since the local mechanic most likely hasn't been trained on a B-Class and I suspect the dealer wouldn't cooperate.

Or from what some people say the dealer quoted them for repairs, you could probably ship the dang car to California and back and still come out ahead!

Charles Hall
Raleigh, NC

No local mechanic on the east that I know of can do this. Your choice is the dealer who usually has one trained tech on our B250e or shipment to California to someone like Tony and back for roughly $1250-1500.

From what I read, 40K is the magic mileage for worn bearings on early Tesla motors. There is also the issue of coolant leaks into the motor as reported on this post which can happen earlier. There are youtube videos of Tesla motor issues and repairs if you are curious.
Hello all. It’s almost been a year since I’ve owned my BE. Smelled coolant while at a stop. Took it in and I was told it’s leaking coolant and will need a new Drive unit. This will be the 3rd replacement. This has happened to all 4 units the car has had. I’m only at 25k.

I didn’t want to discourage anyone from buying the car, it’s a great vehicle to drive but something is going on. This shouldn’t be happened so often.

This is quite unusual and has got to be very frustrating for you. Very sorry to hear. I assume the dealer is covering all the expenses and providing a loaner car.

Since this is the fourth engine, you may want to have a discussion with them about buying you out. I would be worried that something else is causing the motors to fail in your particular car. Don't settle for less than what you paid for it in any case.

Please keep us posted as it is helpful to know the bad along with the good.

Good luck.

I am experiencing the same problem with the coolant and drive unit. I tried to find your complaint at the NHTSA and was unable to locate it. I would like to reference it in my own complaint. Do you have a reference number or anything?


For your motor/coolant problems, were all of your repairs done at a mercedes dealer? Did an independent mechanic ever look at the problem?

Dealer says my b-class has the same problem, and electric car specialist can't find anything wrong. ??


So I received the "coolant in battery...drive unit needs to be replaced" pitch from the MB dealer last month as noted here. Since then, I had the car towed to an electric car specialist. They checked the level of coolant (full) and pressure tested it. Pressure test was good, coolant level hadn't changed, and there was no coolant in the motor. Large battery is not throwing any MB codes that indicate it's having a problem. All of the MB codes are indicating problems with 12V battery and electrical. The car is not recharging the 12V motor.

So what's the deal? Is MB defrauding us? Negligent in that they know there's a problem that the new DU fixes temporarily? Or what?

Has anyone had this electrical issue and fixed it by doing something OTHER than replacing the drive unit?
My Mercedes B Class 2015 is at the dealer for a DU replacement, it broke when my wife was traveling in the fast lane of the expressway, fortunately one ranger was going in same way and put his emergency lights to avoid a tragedy. There are still angels in this world.

My car has 36000 miles and 4 years warranty expired two months ago.

Someone at Mercedes head quarters should take note of this critical issue and recall all of these cars that are running with a high risk for their owners, as Tesla did with his customers for same problem in his cars. Never is to late to save lives.

There is no explanation on how Mercedes Benz sold cars with a lifespan less than 40.000 miles and no more than five years life.

New Drive Unit job will be around $10,000 not including surprises at the time they remove and install the new DU.

If someone has a good contact at MB to who we can send our complain, I will greatly appreciate that information.