Advice needed, weird noise appeared

[Rolf68]

Hello everybody.

I'm looking for some advice, in case the same thing happened to someone here.

Since yesterday, my car makes a strange noise while driving.

It's hard to describe, it's a kind of mix of light friction noise (a bit like when the brakes rusted after being wet and sitting some days) and a vacuum blower (like a long low-pitched WHOOOOOOOO). The noise varies with speed, start when driving low speed when the car parked for some times. Then it continues for a while, stil varying with speed. It also sometimes disapears at high speed. And I could also hear noises like when air is released from a tank, some quick "pchiiit" ...

I'm a bit lost, what can this be? I have no alert on the VDS (I'm in debug mode), the car drives fine and the temperatures in are all in the normal ranges. When I charge the car all is ok.

Mit rough guess would be something with the motor blower, maybe something stuck on one side ??

Any hint / advice?

Thanks and have a nice day

 

[Stefan T]

wheel bearings

 

[Mitrovic]

I had strange noises while driving and had the gearbox replaced. The noises changed with speed.

 

[bolosky]

I have a somewhat similar thing that just started happening to my car, and I think it's wheel bearings. It's strange, something in my monkey brain hears the pitch go up and keeps telling me to shift.

 

[ShawnA]

Hi Rolf68,

Air conditioner blower in the cabin???
Soft top / Hard top? Any type of wind noise?
The PEM and motor fans are constant speed - aren't they?

Are the electric fans over the "radiator" variable speed?

Sorry for all of the questions...
Perhaps one could point you in the right direction...

Shawn

 

[DeedWest]

Does it vary at different speeds & throttles?
If so, it could be the drive unit.

 

[gregd]

Also, can you isolate the noise to a quadrant of the car (front/left, etc)? Referring to the blowers suggests it's in the rear, yes? Does it change in intensity when you corner (turn)? After the car's been driven for a while, or right when everything's cold?

One technique to hear the sounds better is to roll down the window (or remove the top) and drive by a solid wall, which will act as a reflector.

 

[Rolf68]

Wow, thanks for all the answers, you guys are great for support

I'll try to answer all the questions in the same post, sorry if I forget some

No air conditioner or fan in the cabin.

I got the hard top on, but it's clearly not a wind noise. Happens also at low speed.
yes PEM fans seems to be constant. Dunno for the motor as I never heard then.
It's not the fans on the radiators, thos do only trigger when air conditionner is on, or while charging.

the sounds seems to come from behind me, the rear left corner of the car. I rolled the window in order to hear better but is seems you can hear it better with the window closed (no wind noise to interfere)

The noise starts as soon as I drive the car, when it's completely cold. It goes high and low varying with the speed, but I cannot tell if it change in corners.

I best thing I thought of to describe the sound is something like an old computer fan turning, you know when it's soooo old and it makes a long low pitched "whoooooooooo whooooo". It's really sounding like that.

Tonight I'll go to see a friend who got a car lift, and we'll have a look at that from under the car. We'll remove the rear shield plate and look at everything we find there.

I hope we'll be able to check the wheel bearing (didn't think of that, thanks for the advice) and see if any road debris is stuck near the motor.

Is it safe to drive with bad wheel bearing?

Is there a way to check the motor / drive unit ? I did put the car in neutral and I pressed the accelerator to see if the motor would spin and make the noise but nothing happend. I'm not sur it would be safe to lift the rear and spin the tyres for real...

Thanks again for your help, I'll keep you informed about what we found.

Kind regards

 

[Mark77a]

It doesn't sound like wheel bearings to me.
I'd check motor blower fans, even a piece of grass getting sucked in can cause noises and the speed of the fan does change (although not necessarily in proportion to road speed) . Fans also can run when charging - is the noise then ?
Also bits of grit stuck around brake calipers (although these usually wear away eventually) .
Loose sound deadening wheel arch trim rubbing ?
And dont laugh ... radio tuned to LW (picks up motor and electronics noises).

 

[Rolf68]

Kello Mark77

No noise when charging. I also though of something in the blower but I'm not sure it would vary so much with driving speed, the fan should remain more or less constant, especially when the car is cold in the morning.

We'll check the brakes tonight. I pressed them a couple of time really hard but no effect so far.

I'm not sure what you mean with "Loose sound deadening wheel arch trim rubbing " . I visually checked all what I could around the wheel and I saw no sign it touches anything around.

I don't use the radio tuner, I just play spotify using my phone and BT link, or some MP3 from a USB stick. I muted the radio anyway since I started to hear this sound, so I don't think it's electronic noise either.

Have a nice day

 

[scottm]

"whoooooooooo whooooo"

if you're rolling sound could be rubber on the road... out of round or irregular wear pattern due to alignment, or some kind of tire defect with tread or shape now that it has worn down a bit may have been disguised when new with lots of tread to soften the effects

inspect tires and tread wear closely

rotate the tires and see if the sound moves to the opposite side of the car


brake friction / warp
wheel bearing?

these things can be felt by hand

jack the car up at the corner, one at a time

rotate the wheel very lightly and constantly with a finger or two... does it "catch" and slow down at some position in the rotation ... rubbing on a pad? Look for disc warp

spin the wheel (have someone else do this) make sure the brake friction pads are not touching the disc... ...as you put your hand on the backside of the hub by reaching around... do you feel anything "gritty" in the hub? ... that's a bad bearing. If you have a mechanics stethoscope, use it and you'll hear the bearing rollers not having a smooth ride

 

[rhumbliner]

Had something similar on my MS. Turns out the Tesla Ranger found a stone wedged under the rotor cover. I don’t know what a rotor cover is — those were his words — but he fixed the problem in a few minutes.

 

[scottm]

Had something similar on my MS. Turns out the Tesla Ranger found a stone wedged under the rotor cover. I don’t know what a rotor cover is — those were his words — but he fixed the problem in a few minutes.

There's a somewhat flimsy piece of round cut sheet metal on the car side of the brake disc, meant to keep road debris out of the brakes... ya, sometimes rocks of just the right size get wedged in there and scrape. It's more of a scraping sound

 

[gregd]

Be really really really careful when trying to raise the car by any means. Specifically, putting it up on a lift can wreck the car if it's not done right (generally requires adapters). Jacking points are in very specific places. Please check what the manual says on the topic.

What you describe about the "old computer fan noise" is probably significant, but I can't think of any fans that run when the car is moving that don't also run when it's sitting there charging. The only bearings that fit that description are the wheels, but in my experience they sound more like a large robot lunching on bits of metal (which, when you think about it, is exactly what is happening). Driving on a bad wheel bearing is a really bad idea. Maybe the axle joints (whatever they're called)? But again, more likely a grinding noise.

Tire noise is a possibility, but how fast do you need to be moving to hear the noise? If it's slow, that probably isn't it. If you do rotate the tires, check to see if they are directional first. Some cannot be run safely in the wrong direction.

I'm voting for something in the brakes. Are you due for new brake pads? That kind of sounds like the noise made by metal-on-metal contact (pads minus the friction material against the rotor).

 

[X.l.r.8]

just throwing this out there, is your stereo off it could be your speaker picking RF interference. I'm sure the system is well shielded but I never rule out the obvious

 

[Rolf68]

Hello all.

Again, thanks a lot for all you answers and advices. Very valuable

So yesterday I went to my friend and we did a close examination of the car. I drove the car on a lift and he carefully examined everything we could see from under, seeing nothing wrong.

We then removed the back plate under the car (dunno the name of the piece, a "shield" ??) and had a look on the fans. There where some leaves in them, but nothing serious

Then we decided to lift only the rear part of the car to let the rear whell spinning. It was a bit fun to find how to safely do that. We finally put a long wood board across the car right under the jacking points and lowered the lift on some stack of stuff, in order to let the rear wheels be free. We had to attach the front wheel as the car wanted to be on balance on the board See the picture to get the idea :



Once the car in position, my friend first turned the wheels manually and checked the brakes and bearings. Everything was ok, and so where the tyres. The last test was then to start the car and accelerate gently. So I jumped in, turned it on and removed the TC. I then put the car in "Drive" pushed very little on the "gas" pedal and the wheels spinned, and we could clearly hear the noise even at low speed in the calm of the garage.

My friend then used a mechanics stethoscope to check all the parts. We did the same in "Reverse", and the noise was there also.

After those final test, the origine of the noice was identified as coming from inside this piece :



My friend told me it must be gearbox, and he suspects the oil inside is now too old to be efficient anymore. So his first advice is to simply change the oil as a quick fix in order to see if that improves things. Then later we could consider to change the whole stuff.

But to do so he'll need to know the exact type and amount of oil required in this box, and if there are some special things to do when changing it, like the need to heat the oil before putting it in for example (I'm not a mechanic, for me it's wizardry so I just ask for him)

So, anyone here knows how to change the oil in there? And other question, any idea how much does this piece cost as new part and / or from a salvaged car?

I really hope an oil change will fix the car for some times, without having to go through a service center as it would be much more costly there.


Thanks a lot everybody, you guys are awesome

Best regards

Edit : just found this video :

The guy says oil should be replaced every 2 years.

Also found that Gearbox Oil and Transmission Oil TESLA ROADSTER Electric 252 HP » low prices

Is it reliable as oil choice ??

 

[gregd]

The user manual I have shows the "Transmission fluid" as Dextron VI ATF, and a capacity of 1.4 US quarts, or 1.325 Liters.

There's no mention of a periodic replacement for the fluid, and I seem to recall it being something like 10 years / 100k miles or thereabouts, definitely not as frequent as 2 years. I just had my 2.0 Roadster in for its yearly maintenance and leaf removal, and the tech noted that I was due for the 4 year coolant and 2 year brake fluid flushes (I think those were the numbers). They were both so clean we decided I could wait until next year (I need to invest in new tires this summer), but never did he mention the transmission. I have 47k miles on the 8+ year old car.

If your transmission is making the noise, I suspect a simple fluid change won't be sufficient for a fix. But perhaps looking at the fluid extracted will give a clue as to what is happening inside. Good luck!

 

[Mitrovic]

Well as I mentioned it happened to my car, too. Twice.
Both times it was under warranty and Tesla replaced the gearbox.
It is a Borg Warners unit. The second time there was a wait as the unit was not available.
No idea how much it costs as it was under warranty.

 

[Rolf68]

Hello Gregd and Mitrovic

I know a fluid change will not fix definitely the problem, but at least I hope it will help until we can find a replacement unit. My car is also 8+ years but is already well over the 100k miles (something like 116k).

Maybe it's possible to find some kit through "Borg Warner", or from a salvaged car with less miles. It's a pity we don't have access to maintenance manuals

Anyways thanks everyone for the help. We'll make the oil change monday morning, until then the car will stay quietly in the garage.

have a nice day

 

[X.l.r.8]

Its probably a bearing on the casing to the output shaft. These would be serviceable due to the simplicity of the transmission