Hissing whining sound on acceleration

[wizardj]

Hello from france, new on the forum
So the class b has about 100 to 120 kms autonomy , I don't have range plus on this 2016 model and it has 113000kms .
No warning signals or errors onboard, and the car is in guarantee untill February.
Now when I accelerate I hear this high pitch sound when on zero no sound only on acceleration and when recharging the sound seems minor normal, now I have driven other electric cars I don't get this sound on acceleration, i tried to call Mercedes about this if it was motor problem since I have read about similar issues, they told me I have to go get the car checked and if there is a problem they will if the participate in fixing, called the local dealership and they never called me back , one problem being it seems no one knows this model or is qualified in the south of France on this type of véhicule.
I will upload a video this week so people can hear the noise I am talking about.
One question is Because this is my mother's new car to drive around, does it make high pitch sound when you accelerate? Is it normal ? The seller said it was the sound of the electric car, thinking I never had an electric car before , my two other electric cars experience are pretty much silent.
If any one knows of some expert in south of France, or how to contact mb or tesla for motor guarantee,
Or just how long can we drive with this hissing sound before car or motor needs to be replaced. Any help welcome , I ve never used mb guarantee either , so no idea about protocol.
Thank you and other than that it's a lovely powerful drive , I'm impressed by this car outside the short range In my case a solid 100kms but it's winter , I was hoping for 150/160kms , so could it be motor friction that looses the range or used batteries ?
Any hack to change the panel or to get range plus update welcome . Best greetings.

 

[nrkmann]

Hello from france, new on the forum
So the class b has about 100 to 120 kms autonomy , I don't have range plus on this 2016 model and it has 113000kms .
No warning signals or errors onboard, and the car is in guarantee untill February.
Now when I accelerate I hear this high pitch sound when on zero no sound only on acceleration and when recharging the sound seems minor normal, now I have driven other electric cars I don't get this sound on acceleration, i tried to call Mercedes about this if it was motor problem since I have read about similar issues, they told me I have to go get the car checked and if there is a problem they will if the participate in fixing, called the local dealership and they never called me back , one problem being it seems no one knows this model or is qualified in the south of France on this type of véhicule.
I will upload a video this week so people can hear the noise I am talking about.
One question is Because this is my mother's new car to drive around, does it make high pitch sound when you accelerate? Is it normal ? The seller said it was the sound of the electric car, thinking I never had an electric car before , my two other electric cars experience are pretty much silent.
If any one knows of some expert in south of France, or how to contact mb or tesla for motor guarantee,
Or just how long can we drive with this hissing sound before car or motor needs to be replaced. Any help welcome , I ve never used mb guarantee either , so no idea about protocol.
Thank you and other than that it's a lovely powerful drive , I'm impressed by this car outside the short range In my case a solid 100kms but it's winter , I was hoping for 150/160kms , so could it be motor friction that looses the range or used batteries ?
Any hack to change the panel or to get range plus update welcome . Best greetings.

I think you need to schedule a visit to the dealer. I am in the US so EPA range is 87 mi standard (140km) and 105 mi with range extension (168km). The battery is guaranteed for 8 years but is supposed to have a new desiccant filter installed every year. While there have them diagnose the whine. I bet it might be the transmission bearings. You want to have the bearings replaced, you normally don't need a new unit, before the damage is too great to repair.

 

[wizardj]

I think you need to schedule a visit to the dealer. I am in the US so EPA range is 87 mi standard (140km) and 105 mi with range extension (168km). The battery is guaranteed for 8 years but is supposed to have a new desiccant filter installed every year. While there have them diagnose the whine. I bet it might be the transmission bearings. You want to have the bearings replaced, you normally don't need a new unit, before the damage is too great to repair.

Thank you for the information about the transmission bearings , it might be that I will update with a video. Best greetings.

 

[jjo]

I second the gearbox bearings. There are two rather basic bearings 6207 and 6208 on the incoming side and it spins at the same RPM as the rotor, up to 12000. They wear out and cause this whining noise, it's the same for all early Teslas and the Toyota RAV4 electric. Search for "Tesla million noise" on Youtube.
The good news is that the drive unit can be opened at the gearbox without opening the motor part.
You need the two bearings above, 2 litres of transmission fluid and two seals for the axle shafts (same size as BMW and other brands). The bearings are usually only available as 2RS so the mechanic will need to pry off the dust covers on both sides as the bearings are lubricated by the transmissions fluid itself.
I've got this fixed and my car is (near) silent again. 167000km currently.

Forget about the Mercedes-Benz dealerships: the only repair they will offer you is a replacement of the complete drive unit at your cost (way over €10,000). Find a garage the repairs Teslas, they will know everything about the B-Class and will be able to repair it for you. It is the same drive unit (motor) as the one in the early Tesla model S cars.

If you know a good mechanic, they can also fix it, there is quite a lot of info online. I'm happy to help with any details. My mechanic said fixing this motor was 10x easier than any petrol or diesel engine.

 

[asavage]

A bit of additional info: the drive unit is not the same as Model S, it merely has a lot of interchangeable parts. In the B250e and RAV4 EV, it's mounted reversed, the gears have their angle reversed, the oil pump is reversed, the case halves are different (to accommodate electric Park), and the MB has an additional interface board on the inverter side. You can't, for example, buy a Model S drive unit and install it in your MB, not even close!

The motor end is pretty much identical (troublesome coolant seal, troublesome rotor bearings, Aegis ring on our early units) but the gearbox has few interchangeable parts. And the brgs that fail are the rotor bearings, not gearbox bearings; early production units had insufficient rotor induced current grounding via an Aegis ring ("whisker brush"); rebuilds get ceramic ball bearings for the rotor, moving the rotor grounding to the gearbox pinion bearing and pinion gears, which is why that first gearbox bearing is typically replaced when the rotor is out for new bearings or seal surface repair, and why the pinion gear sometimes has pitting.

Howard Cheug (Seattle area), Johan (Calif.) and many others have been deep into the LDU and have extensively documented it, as possible with so many variations by Tesla over the years. Neither Tesla, Toyota, nor MB are interested in supporting these "old" vehicles, so it's on us to do what we can.

 

[jjo]

I think you need to schedule a visit to the dealer. I am in the US so EPA range is 87 mi standard (140km) and 105 mi with range extension (168km). The battery is guaranteed for 8 years but is supposed to have a new desiccant filter installed every year. While there have them diagnose the whine. I bet it might be the transmission bearings. You want to have the bearings replaced, you normally don't need a new unit, before the damage is too great to repair.

Just to reduce anxiety: 140km might be achievable in a mild or warm weather, 100-120km is perfectly good in January, in France. it will be more around the 130-140km range in summer.

 

[wizardj]

I second the gearbox bearings. There are two rather basic bearings 6207 and 6208 on the incoming side and it spins at the same RPM as the rotor, up to 12000. They wear out and cause this whining noise, it's the same for all early Teslas and the Toyota RAV4 electric. Search for "Tesla million noise" on Youtube.
The good news is that the drive unit can be opened at the gearbox without opening the motor part.
You need the two bearings above, 2 litres of transmission fluid and two seals for the axle shafts (same size as BMW and other brands). The bearings are usually only available as 2RS so the mechanic will need to pry off the dust covers on both sides as the bearings are lubricated by the transmissions fluid itself.
I've got this fixed and my car is (near) silent again. 167000km currently.

Forget about the Mercedes-Benz dealerships: the only repair they will offer you is a replacement of the complete drive unit at your cost (way over €10,000). Find a garage the repairs Teslas, they will know everything about the B-Class and will be able to repair it for you. It is the same drive unit (motor) as the one in the early Tesla model S cars.

If you know a good mechanic, they can also fix it, there is quite a lot of info online. I'm happy to help with any details. My mechanic said fixing this motor was 10x easier than any petrol or diesel engine.

Win, thank you for sharing this, it would be great to share more information maybe for the diy guys out there, not a mechanic but might it give it try to fixing it myself or at least understand better , cheers

 

[jjo]

Win, thank you for sharing this, it would be great to share more information maybe for the diy guys out there, not a mechanic but might it give it try to fixing it myself or at least understand better , cheers

I'm happy to help anyone but all the info I gathered is already available online in this forum, the Facebook group https://www.facebook.com/groups/bclasselectric and various Tesla forums. Youtube has repair videos too, I think for the Rav4.
I was consulting to someone from Hungary who did the exact same repair so I had a confirmation beforehand that the two bearings indeed fix the milling noise, and that the rotor side does not need to be opened for this.

 

[Hussain]

I second the gearbox bearings. There are two rather basic bearings 6207 and 6208 on the incoming side and it spins at the same RPM as the rotor, up to 12000. They wear out and cause this whining noise, it's the same for all early Teslas and the Toyota RAV4 electric. Search for "Tesla million noise" on Youtube.
The good news is that the drive unit can be opened at the gearbox without opening the motor part.
You need the two bearings above, 2 litres of transmission fluid and two seals for the axle shafts (same size as BMW and other brands). The bearings are usually only available as 2RS so the mechanic will need to pry off the dust covers on both sides as the bearings are lubricated by the transmissions fluid itself.
I've got this fixed and my car is (near) silent again. 167000km currently.

Forget about the Mercedes-Benz dealerships: the only repair they will offer you is a replacement of the complete drive unit at your cost (way over €10,000). Find a garage the repairs Teslas, they will know everything about the B-Class and will be able to repair it for you. It is the same drive unit (motor) as the one in the early Tesla model S cars.

If you know a good mechanic, they can also fix it, there is quite a lot of info online. I'm happy to help with any details. My mechanic said fixing this motor was 10x easier than any petrol or diesel engine.

 

[Hussain]

I agree with you Ihave a little hissing sound when I move the car at any stop but noise go away when speed reach to 35 and over, MD said change the motor but I think this is just 2 bearings,please let us know approximately how much cost to replace these bearings

 

[jjo]

These were the parts that I needed, total cost was appr. €110
- 6207+6208 SKF Explorer C3 bearings - ~€70
( I bought them at the local bearing specialist to make sure they are genuine SKF, not fake)
- 2x axle shaft seals https://www.ebay.co.uk/itm/173811815168 - ~€10
- 2l gearbox fluid: https://www.ebay.co.uk/itm/163960288581 ~€30

And the labour was about 10-15 hours, that largely depends on your mechanic.

 

[asavage]

Only the very early DUs used those bearings; all remans after a certain year (and all new DUs) used similar bearings but with ceramic balls in the bearings, non-conductive. The original Aegis ring in our DUs, designed to route to ground stray induced current in the rotor, turned out to be ineffective, and the stray currents went through the ball bearings instead and adversely affected their service life.



Installed:



Longer view:



Later DUs with the ceramic ball bearings moved the current path to the pinion gear and its ball bearings [rolleyes]. They appear to last OK, until leaking coolant washes the grease out of the outside end one

The bearings you want to use are:
6007-2RZTN9/HC5C3WT-SKF
As noted, there are many counterfeit SKF bearings on offer, so it's best to buy from an authorized SKF distributor. I bought mine last month from:
https://www.acorn-ind.co.uk/p/skf/single-row-deep-groove-ball-bearings/6007-2rztn9/hc5c3wt-skf/
$114 ea.
They had by far the best pricing I found; you will find these offered at twice the price by US distributors, and half the price on eBay (again [rolleyes]).

 

[asavage]

Now when I accelerate I hear this high pitch sound when on zero no sound only on acceleration and when recharging the sound seems minor normal, now I have driven other electric cars I don't get this sound on acceleration,

If the sound is hissing and high-pitched, and the pitch can be modulated by the accelerator pedal, it may be a different common problem with the early Tesla Model S which our cars share: "Battery Contactor Squeal", Tesla Tech Note TN-13-16-002 R1, 13 Sep2013

https://www.myrav4ev.com/threads/all-posts-replacement-traction-battery.1803/page-4#post-28898


Might not be LDU rotor bearings at all.

 

[jjo]

Only the very early DUs used those bearings; all remans after a certain year (and all new DUs) used similar bearings but with ceramic balls in the bearings, non-conductive.

That is false.
The milling noise is caused by the two cheap SKF bearings I quoted in the gearbox, not the motor. The rotor side does not even have to be opened for the fix, the gearbox comes apart without touching the rotor side.
I know because my car is now silent after changing those two cheap bearings one year and 15k miles ago, I also talked to another owner who got the noise fixed the exact same way.
See my own photos attached of the old bearings that were removed.
The problem is that these bearings are spinning at the same RPM as the rotor as they are on the incoming axle and they wear out premature.
Again, the part list I provided was all I needed to get the motor silent again.

 

[asavage]

OK, with a sample size of TWO, those pinion brgs go bad, can be replaced, and the noise is gone.

With a sample size of THOUSANDS, the original, steel ball bearings erode from induced rotor current and cause milling noise, which was ameliorated by Tesla updating the rotor bearings to ceramic ball bearings.

If the OP's DU hasn't been replaced by a later reman DU (ie after maybe 2014?) then it'll have the steel ball rotor brgs and they "always" fail -- probably more than 70% of the early Model S units have been replaced specifically for this issue, aside from rotor coolant leaks.

 

[jjo]

OK, with a sample size of TWO, those pinion brgs go bad, can be replaced, and the noise is gone.

With a sample size of THOUSANDS, the original, steel ball bearings erode from induced rotor current and cause milling noise, which was ameliorated by Tesla updating the rotor bearings to ceramic ball bearings.

If the OP's DU hasn't been replaced by a later reman DU (ie after maybe 2014?) then it'll have the steel ball rotor brgs and they "always" fail -- probably more than 70% of the early Model S units have been replaced specifically for this issue, aside from rotor coolant leaks.

I'm sharing my experience and I have the early drive unit, my car is the ED from 2015. I have enough of people scaremongering owners believing the issue is bigger than it is.
Opening the rotor side while no Teflon seal available on the market other than a Chinese make is a really bad decision and I strongly discourage it.

 

[asavage]

Tesla has given up on liquid cooling the rotor on LDUs, after trying 1-lip seals, 3-lip seals, and multiple rotor resurfacing methods.
https://teslamotorsclub.com/tmc/posts/7898613/

Unlike pretty much every other water pump seal design in the world, Tesla did not design in a weep hole. All leaks at that seal result in trapped water/glycol and eventually inverter destruction. Years ago, QCC offered a "drain kit" so you could see the blue coolant an your garage floor well in advance of the coolant making it to the inverter. Now, they offer an aftermarket "coolant delete" kit instead, so no seal to leak.

Ignoring the problem by not checking for for coolant on the rotor speed sensor costs a lot more than checking it often.

Rotor seal failure is the number one failure of the LDU. Bearings failure of the rotor -- on early units -- are number two. Gearbox issues (bearings, spider gears in the diff) are way, way down the list.

"When hearing hoofbeats, think horses, not zebras"

Scaremongering is warranted with these drive units: they are time bombs. Tesla and RAV4 EV forums are crowded with LDU failures. This is not something to be downplayed, it's the first thing that an owner should worry about. It's one of several reasons buying a used Model S (or B250e or RAV4 EV) is a bad idea, unless you go in fully informed of the risks of this design and know the risks. I bought my '14 in '17 knowing in advance that I'd be removing and repairing the LDU "someday", and last month that time came.

I pulled my LDU 13 days ago for coolant ingress, and it goes back together next Wednesday. 60k on original, got a warranty reman due to rotor bearing noise. I got another 55k on the reman before coolant appeared on the speed sensor, and I pulled it apart early enough that my only damage is limited to the last 3" of the rotor & stator, my stator still passes insulation resistance testing at 4.7Mohm rather than being ruined by sitting in coolant long enough to break down the insulation, rendering it economically unrepairable. If I'd stuck my head in the sand, not checked for coolant at the first sign of issues ("Check EV System", the Toyota equivalent of MB's warning), and kept driving it ("it doesn't mean anything, it drives fine, I'll ignore the warning") then rather than faced with a sub-$1k repair I'd be buying a different LDU and having it rebuilt, because mine would be un-salvageable. Or, the car would be sold for parts.

On these early LDUs you ignore the dash warning at your own economic peril. There are a LOT of these being scrapped, largely for the same reason: uneconomical to repair the LDU.

 

[jjo]

That's a nice, long writeup, HOWEVER: it has very little to do with the milling noise.
I'm really sorry that your LDU got the water leak but it doesn't mean 100% of the LDUs get broken.
I'm aware of all the info in your post, scaremongering is still not warranted.
Yes, we all have to check the rotor position sensor regularly and act at the first signs of leak.
Milling noise can be repaired at a much lower cost.

If you think about it, it makes sense: there are two robust bearings on the rotor. There are 2 cheap bearings on the incoming axle of the gearbox which is spinning at the same RPM as the rotor, up to 12000.
Which bearings will give up first, in your opinion?

I'm not saying that the leak is to be downplayed, I will get the coolant delete installed at one stage. I'm just saying that the milling noise can be something else.

My drive unit is original, at 105k miles, no leak. I'm pretty sure mine is not the only example.