Annoying noise from inside dash ??? Where/What ???? - The Unofficial BMW M5 Messageboard (m5board.com)

IvanDias · 27th February 2003, 17:05

Guys,

I`ve a horrible noise, it started out as just a light whirr, as if a fan bearing was worn (like when a computer cpu fan gets old), then it changed to a bad whirring when cold, then light after a few minutes, but now it`s a horrible low pitched grinding whirr constantly.

The noise starts anywhere from immediately the car is started up to about 5-10 seconds after the engine starts, and goes off sometimes a little later (5-30 mins), sometimes never until the engine is killed after parking.

I have a RHD car, so the passenger sits on the left. The noise is coming from in front of the passenger, above the glovebox, there`s a recess for storage on top of the dash, with the speaker to the left and the grill for air (?) in the middle of the dash.
It`s coming from around or under the storage recess, more towards the windscreen than the glovebox front.

I`d thought windscreen adjustment motor, but that`s on the right hand side by the steering wheel on a RHD isn`t it, so it can`t be that ??

Turning the fans on from off-1-2-3-4 makes no change, nor does pressing the button to make the air recycle inside the car.

The air-con is non-functional on my car, but pressing the button doesn`t make the noise change anyway.

Doesn`t sounds like an earthing issue with the speaker, it`s not soming from there.

Finally, the noise does change in pitch ever so slightly as you drive along, but it is random +/- 10% maximum, and is not related directly to engine rpm or actual speed in a gear.

Any ideas before I start to pull the dash apart ????

Is there anything windscreen wiper related on the left hand side of the engine bay of a RHD car?

HELP !! It`s doing my head in !!!

ilundber · 27th February 2003, 20:32

Hello IvanDiaz,
I don't know if there is something from the wipers in front of the pasenger side of a RHD-car, but my guess would be that one of the small electrical motors that control the air direction (to the windscreen, to the vent in the dash etc) is gone. I have something of the same problem. Sometimes it makes a very loud noise approx 30 sec after I have started the engine and it keeps making the noise for about 30 - 60 sec.
Taking the dash out took about an hour of work, even for a beginner like me. I did that last summer. The only thing that you need to do in order to make life simple is to dis-connect the four big electrical connectors on the left hand side under the dash( on a LHD car) and the connectors to the temperature control at the centre and the wiring going under the central console. That way you won't have to cut all the wireing loose from the dash as I did out of ignorance.
You have to take down the cover of the A-colons in order to be able to loosen the screews there and you need to undo the two bolts under the dash.
There are, if I remember correctly, four motors under the dash that you then can investigate.
Putting the dash back is also quite simple.

Regards, Ilundber

JP · 27th February 2003, 21:40

First tought whas : whiper-arm-tensioner broke/stuck aswhell .(but rhd ? )
Noise really resonates , so could be , stuck heatingv. ,direktional....aso...,
They do work independed off fan setting .
try feeling if the commanded heat goes the chosen side ,
and only that ! (< ^ >) .
that way , no need for dis and asembling ( for diagnosis ) .

de Witt · 28th February 2003, 07:28

If it is not changing pitch or stoping when you change the air from 1-2-3-4, then I would rule out a fan bearing. Usually when a fan bearing is blown, a lower speed will produce a much slower/louder noise and a higher speed will reduce the faster/noise or the noise will go away. That is from my experience.

Is it making a quick chirping noise? RPM shouldnt have an effect on the fan bearing.

I guess BMW just swapped sides on an RHD. I have to think what might be over there....

jack880 · 28th February 2003, 11:42

hello
I don't know about the M5, but I had a RHD 320i and the wiper motor was in front of the passenger. I read somewhere (probably this messageboard) that the wiper motor on the M5 winds up when the car is started to hold the wipers down in case you decide to do 150mph... Maybe yours isn't stopping and keeps trying to tighten itself?? My car makes a whirring noise from the dash after it's started that stops after 5 to 10 seconds. Dunno if any of this is any use, probably nothing you don't already know!

IvanDias · 28th February 2003, 12:07

That`s what I suspected, the magical M5 wiper pressure motor, but I understood that this was on the drivers side only, which is why I asked you clever guys out there if there was anything else I`d be checking before before the dash comes off.

Thanks, please feel free to continue if anyones had this problem.

I might just post a little video or soundclip of it. Would this help?

Ivan

Donati · 28th February 2003, 15:55

Soundclip could help.

You are talking about "blown fan-bearings noise", did you check the cooling fan located under/behind the DME/ECU?
In my LHD car its located on the right side of the car, just under the box that holds the DME/ECU.
I dont know if this is moved to the left side of a RHD car?

This fan runs as soon as you turn the ignition on, before the engine is started.
It makes a sound exactly like a computer PSU cooling fan, and
at first i thought it sounded like it was coming from somewhere behind the glovebox.
I noticed this fan when i was changing my ecu chip, and since you have also an aftermarket chip, maybe you have noticed this fans location also?

mikek · 3rd March 2003, 01:05

Ivan,

Could it be the cooling system inline electric water pump that sits on the passenger side of the car. It is used in extreme circumstances to pump the engines coolant at a higher rate when the ordinary water pump cannot cope???

IvanDias · 3rd March 2003, 11:20

I`ll get the garage to check, but I`d hope not, it had a new water pump 4000 miles ago.

Ivan.

Alan Archer · 15th March 2003, 11:48

I would surgest isolating fuses to see which circuit the noise
belongs to before going the whole Hog with the dash senario !!!

Afterall, you can live without the wiper tensioner so long as you stay below 140 Ivan !!

Regards,

Alan.