Motor whining, needs replacement

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Four months is outrageous. Mercedes should extend the warranty for at least the amount of time they had the car if not a full extra year!

One month sounds better but still there is the principle. Definitely write to the German CEO and let them know that this is no way to treat one of their double customer who is helping them learn at our expense.
Our car is a fine car but Mercedes has discontinued it. As such the parts come from Germany. My car was out of service for 2 months waiting for a part. Mercedes has an obligation to support it but it takes a long time.

I rad out of the State Farm loaner money so the dealer gave me a C100 loaner. It seems that Mercedes will give you an ICE loaner. It was the first time in several years I had to buy gas! They fulfill the warranty but you need to be prepared to wait.
Ferdball said:
Got part on Monday, dropped off car Tuesday. Going to pick it up today. Here's what the invoice says.

18300 W30
01 242-340-42-01-80 REMAN ELECTRIC DRIVE

Hey, can you elaborate on the original diagnosis by the techs? Was it strictly subjective (that IS a loud whine) or was there an objective finding (Code xxx indicates motor flaw).


Four months is a long time but having a Mercedes supplied loaner negates that. The only problem is that the loaner is most likely ICE so you need fill it with gas.
I'm looking to purchase a used 2015 B-Class, with 3-Months remaining factory warranty. When I test drove the car, I was stunned by how LOUD the car was. It sounded as if there was an engine in the back of the thing at some speeds. It was loud.

0-5 MPH - quiet
15-40 MPH - Loudest
40+ I think the road noise started to pickup at this point, and I no longer noticed it.

This is the 2nd 2015 B-Class ED I've test drove, and both had this same experience of a loud noise from the rear. In the first I drove, I thought maybe there was something wrong with the rear tires -- it was so loud.
Currently I have a Ford C-Max Energi, and when it's driving in EV mode (which is always) it's MUCH quieter than the Mercedes was, that really surprised me.

I did note some odd wind noise as I was approaching 45 MPH or so, around the drivers side view mirror, but it went away, so that didn't bother me too much.

I'm in Arizona, and the AC was on. I suppose I should turn off the AC on my next test drive just to rule that out.

Can any owners chime in, is this normal, or is this a sign of trouble / trouble to come? I know noise is hard to describe in text. I'll try to video tape the noise on my next test drive, and perhaps drive a couple other B-Class EDs to compare the noise levels...

My concern is, if this is abnormal noise, and it is indicative of a problem, how much of a pain is it going to be to get a Mercedes dealer to recognize the issue, and own that there is a defect?
I also fear how competent the techs will be at actually replacing the parts -- since this car is somewhat of a unicorn for my dealer. I understand there is one Mercedes Dealer in the Phoenix area that actually services the B-Class units, where the others will not even touch it, so that worries me, too. Any thoughts, suggestions, or things to look & listen for are appreciated!
Gosh there's nothing at the back, this is a front wheel drive car. I guess I would suspect tires or wheel bearings. I mean there's nothing else back there, not even a differential.

As for the dealer, I'd go chat with the one that does work on them. The mechanic at my dealer seems very happy to work on mine. Maybe it's a change from all the diesels. Plus I should think all the dealers will be getting an EV refresher as the EQC rolls out. (Not that that will help you right now.)
Thanks for your reply. I'll go test some more on Friday.
Some thoughts I had: Perhaps a pump or something in the rear, or something related to the battery cooling system could be making noise?
I can't recall if I had the cargo cover open or closed, and that may make a big difference, too.

I agree with your comment, it kind of sounded like wheel bearings to me, but the test drive was too short (they didn't have but 5 miles of range left on the battery when I drove it, so I was limited). Having only 25K, it seems early for wheel bearings though?

Has anyone had any experience with a drive unit replacement outside of the factory 4yr/50K warranty yet? I'm curious how that went (cost, experience, etc)?

Mercedes builds quiet cars and rear end noise means trouble. My advice is to move on and keep looking. For these used cars, whether in warranty or not, don't buy it unless you bring it into a MB dealer to plug in to car computer and read codes and see battery performance. I have leased two of these because I don't want to take tech risk and see no reason why anyone would buy a used one and assume this risk.

I don't recall anyone on this forum who have replaced engine or batteries after warranty. It is Tesla built so you might want to check RAV4 or Tesla forums to find out the ouch cost.
Thanks, Jeff.

Today we test drove two B-Class EDs, back to back, a 2014 and the 2015 we are considering buying.
There appear to be a few noises at play, some present only on the 2015 car we are considering.

Road Noise - this seems to be present on all of the B's, so I'll consider this "normal"?
This noise is likely tires, possibly wheel bearings, suspension, or something like that.
In every B-Class I've been in (4 seperate cars now, two 14's, and two 15's) the road noise is louder than it is in my Ford C-Max Energi, by a wide margin. Today I verified this. I thought the rear cargo cover might help dampen the noise, but it didn't do too much of anything, so I think the tires equipped on the B's must just be louder than what I have on my C-Max Energi (which is equipped with Michelin ENERGY SAVER AS 225/50R17 70895 94V BS). Perhaps because the B's often have run-flats is my best guess for the added noise?

Air Conditioner Noise - maybe fan noise? - Without a doubt the AC system in this car is unique. The system noise seems to ramp up and down - it sort of sounds like when you're on an airplane preparing for takeoff. This noise comes and goes depending on speed, and is even somewhat present at idle. If you drive say up to 40MPH, then come to a stop, after you are stationary, you can hear a somewhat loud humming noise, that then gradually dissipates (like spooling down).

There appears to be an evaporator fan under the hood that adjusts speed when the AC is turned on. When the car is sitting idle, with AC turned off, the fan runs at a very low speed (even though it's 100+ outside). Once you engage the AC, the fan I see in the front, under the hood, likely for the condenser, adjusts speed, and spins much faster, which makes complete sense, seems like a good design. I cannot confirm this fan is the source of the noise though. Maybe a fan mount or something causes vibrations and noise? Maybe the compressor itself is the cause of noise. Unknown currently.

Air Conditioner Noise / Rumble
Even at park, when you turn the AC on, you can actually feel the car vibrate in the front passenger footwell, along with a rumbling noise. It sounds and feels like an ICE car that's sputtering somewhat - it's not exactly smooth. My passenger in the rear said they could slightly feel a rumble (at park) through the floor as well, and they too could hear the noise very clearly - they at least can confirm I'm not crazy.

The backstory on the car
This car I am considering is at CarMax. I had the car transferred in. I have received a full refund for the transfer fee already (wahoo!).
The car is a 2015, with Premium Package, Multimedia Package, Heated Seats, BLIS, South Seas Blue on outside, beige on inside.
25K miles, $16K. Factory warranty remains (Start date of factory warranty: 9/26/2015), 90-Day CarMax bumper-to-bumper warranty also included.

Normally I'd run from this car - too many noise issues that concern me. My dilemma is, finding a car for this price, with these options, in this color, has proven a challenge. Apparently in 2015, not too many B's got heated seats - strange, almost all of the 14's I find have it. Must have been how things were optioned.
Being that this is a CarMax car, and I'd be paying cash for it, I have 7 days to return it, no questions asked. I do not have the option of bringing the car to a Mercedes dealer (myself) prior to purchase, but I do have a 7-day period to do so, risk free, and return if I want (but not hassle free I'm sure).

Where I left things
CarMax will attempt to repair the car. I brought up 4 concerns - 3 of them are easy things I'm sure they can fix, the 4th is the AC noise. I'm under no obligation to buy. CarMax has a service ticket to repair the car. The car is held (no one else can buy it), so I have a chance to review the repairs and see if I'm satisfied prior to buying. I'm not confident they will know how to address the noise issues, and I'm unsure even if they sent the car to the Mercedes Dealer (which they often do I'm told), if the dealer would resolve this concern on the first go.

Where I stand
I'm patient. I'll wait to see if they are able to resolve, if so, I may consider the car. Meanwhile, I will continue hunting. One option I must consider is MaxCare (CarMax's Extended Warranty offering) - I'm not one to pay for a warranty, but a close friend of mine has extensively used MaxCare with extreme success over the years. On one of his 3 MaxCare cars, he had over 26K of repairs to his Audi's - yeah, they break a lot :p, and we're both quite particular. I recall an "ashtray assembly" the Audi dealer replaced using the MaxCare warranty for over $800! Insane.

With MaxCare I'd have essentially bumper-to-bumper 60-month coverage (that would last me into June of 2024 - up to 75K miles, which is fine for me as I don't drive that many miles). The cost for the ESP is a fair ~2K... Not sure I want to spend that extra yet, but, considering it - especially with the unknowns surrounding the drive unit, etc. And all this supposes I actually want to buy this car. I'll report back.

Thanks again!

Ahah, the car is covered by MB warranty till 9.25.19 (four years) and CarMax 7 day. So if you wanna go for it, have CarMax fix what they can, purchase and take to the MB experienced dealer to do a full warranty check on the car, ask them for history and very important have them do battery check. If the prior owner did not do annual battery certification, then the battery warranty will be void. Drive it and if not satisfied, return it.

As to noise:

1. Yes, run flats ride harder and make more road noise. I replaced mine with Michelins all season (am in NE) and the ride was smoother and less noisy.

2. AC noise, mine performs like all my MB cars, when blower is on Max, I hear it. When on Auto, barely notice. Have MB dealer do a warranty check on compressor.

As with all electrics, without the noise of the ICE, you will hear everything else including some wind noise. As these were early compliance cars, MB would not have engineered extra sound protection. There should never be rumbling or rattling, that is a mechanical problem that needs to be traced and fixed.
I took my 2015 B Class into the dealer to have it looked at because of a whining noise when I accelerate. They just notified me that they will be replacing the electric motor drive unit. My warranty on the car is up in another month and does anyone know what the warranty is on the new electric drive unit is?
I had mine replaced under warranty at 47k miles in July'18. MB would never answer that question for me as I was about to have no warranty on the vehicle. They basically said I have the remainder of the 4yr/50k. The also wouldn't sell us an extended warranty as we weren't the original owner. MB had the car for 10 weeks, as we had 3 GLC loaners over that period. Since getting the car back we've put 10k miles on it and it has been performing great. We are hoping it lasts long enough to get a Tesla Model Y when they become available. Good luck, and please post an answer if MB answers
I just got the punch to the gut that I need a new motor. $11,000 !!?? After a few days of the whining noise I took the car in and found it is out of warranty and no help from MB on warranty.

I am extremely disappointed and considering just scrapping the car once it fails. There should be some sort of help given the vehicle only has 40,000 miles on it.

I'm scheduled to have the car in an EV car show this Saturday and will highlight the fact that the total cost of ownership is much higher per mile than an IC engine! 28¢/mile just for reserve maintenance. If I add in the reserve maintenance for the battery it gets more ridiculous.
Ferdball said" Got part on Monday, dropped off car Tuesday. Going to pick it up today. Here's what the invoice says.
18300 W30
01 242-340-42-01-80 REMAN ELECTRIC DRIVE"

What is your invoice said? Is it the same "01 242-340-42-01-80 REMAN ELECTRIC DRIVE" ?



This is bad news. This is a real risk with our cars, both the motor and less often the battery. Anyone buying a used car outside the original warranty period of 4 years is at risk. The battery has a longer term but there is a stipulation that there must be an annual battery check by MB. As yours is a 2014, clearly not covered for motor even if you bought the standard extended warranty which excludes the motor and battery.

When I was contemplating buying my leased 2017 off the lease next year, this risk factored into my purchase price calculation. If what happens to you happened to me, I would consider the car totaled for insurance purposes and try to recover under my auto insurance as a total loss and take anything not covered as a casualty loss for 2019 taxes.

Very sorry to hear.
This board saved my ass! My 2016 B250e has 35k miles and sure enough I tested it and heard that whine sound upon accelerating . Took it to Benz of Las Vegas today and needed a replacement. My Warranty Expires next month. Talk about luck! I agree Benz Dealership needs to look out for this issue. Funny, when I got the car used I took it to Benz and they said all was ok last year! Haha,

Hm, interesting initials but I digress. YES, you are a lucky man. Be sure to get a one-year warranty on the refurbished motor they are putting into your beloved B250e. Study the posts to get all of what you deserve.

Enjoy the ride!
Resurrecting this as I am considering getting a 2017 B250e - out of warranty and not Certified.

Data points from this thread seem to point to 2014-2016 cars having issues w/ defective motor, are the 2017s safe from this perspective? Hate to buy a $16K car to have to plunk $10K for a new motor!

First, welcome to the forum. It was a fun car for 6 years, first a 2014, then a 2017.

Second, don't know where you are but $16k sounds negotiable to me. Be sure to have the car checked out by a MB dealer before you buy to see if all required service was done and to let you know how much degradation of the battery pack has occurred. I miss the car.

Just leased a GLC300 to bridge to a future MB EV. Almost bite on a 2021 GLC350e last year but couldn't pull the trigger during covid when I wasn't driving much. The EQC is not sold in the US or I would be driving that. Yeah, the Burmeister is nice. I listened today for my 3 hour drive by myself. Very nice indeed.