Whistle when throttle at certain positions - BMW Forum

Satori325XI · 10-06-2005, 01:02 PM

Hello, I have a 325XI 2001. I am the 3rd owner, but it is still CPO.

My problem. When the throttle is pressed down, I get a whistling noise. It happens at a range of locations. That is, no whistling sound when throttle is fully up, then at about 10deg press, it begins to whistle, louder and louder til about 25deg at which point it no longer whistles. Until throttle is returned to 10deg-25deg range.

This happens in any gear, any speed, any RPM. It happens when cruise control is active. Passengers dont hear it. Just got new tires and still the same.

Anyone have any idea? Thanks.

drz · 10-06-2005, 01:31 PM

Air filter

peterkulesza · 10-08-2005, 02:51 PM

or a cracked air box. some cretins can accomlish this while changeing the air filter. check the whole housing.

coolkolb · 01-26-2006, 07:07 PM

I have the exact same issue with my 2000 528i. I have scanned all the forums and found out that the throttle housing might just be wearing out or opening up a little when you give it some gas (slightly). No one seemed to be to concerned about it, but it is a annoying sound for sure.

Anyone?

versace · 01-27-2006, 02:52 AM

Do you hear that sound for a few seconds,when you stop the engine?

Satori325XI · 01-27-2006, 07:53 AM

I fixxed this by opening the air intake box, reseating the filter, and properly latching it back.

However, I took it back into the stealer for an oil change and was very precise, "Just the oil change."

As I'm driving away the infamous whistling noise started back up. Bastards messed with the air filter.

And Versace - no it only happened when car is running. I hear the same noise as you, its coming from the back left? I believe that problem was addressed in a previous thread, I am not sure which one. I believe someone wrote that there is a secondary valve that closes near your muffler when you shut off motor? Something along those lines. Nothing to be worried about.

Hootie · 01-27-2006, 10:13 AM

Yeah, this has been recurring for several folks on this board. It doesn't cause a drop in performance and appears to do no harm to your car, it's just a minor nuisance. Mine makes the noise between 2,000-2,500 rpm.

dbrooks · 04-15-2007, 01:22 PM

I only have the whistle when outside temp is > 80 F. I do notice that if it starts to whine if I just lightly use the break pedal (not enough to activate brake lights) the whine or whistle stops. When I shut off the engine the whistle happens for about 4 seconds. I think it's somewhere just ahead of the firewall but can't find it. BTW this is a 2002 300i. I would try and locate myself but I can't finde a repair manual for this car. Any ideas?

Teh Prof · 04-15-2007, 02:58 PM

dbrooks, sounds to me like a climate control fan.

dbrooks · 04-16-2007, 08:22 AM

that occurred to me however even if the climate control is off I get the whine. Is there another fan that I don't have a dash control for?

dbrooks · 05-02-2007, 11:38 AM

More information: It appears to be the climate control settings. If i have the switch set to anything but outside air only then I get the whine above 80 outside airtemp. Doesn't matter if air conditioning is on or off. Whine only happens if switch set to recirculate only or other setting of let the car figure out to switch automatically between outside/recirc.

hamadhayyatt · 05-09-2008, 07:34 PM

hi ive had the same problem on both my old 318's my bro in law who is a bm specialist told me to change the crankcase vent valve with a new one. problem went away on both cars. usually need replacing every 50k or so...

dbrooks · 05-12-2008, 08:07 AM

Had a bad brake booster that had to be replaced. Apparently it uses vacumn and had a leak that couldn't be repaired with complete replacement.

hamadhayyatt · 05-12-2008, 12:13 PM

that makes sense, as the vacuum from the brake servo (booster) comes from the back side of the inlet manifold, in the same place as the crankcase vent valve.. glad youve got it sorted anyhow...

cptdamien · 07-26-2008, 01:17 PM

Hi guys,

I've got the same problem on my 1998 320i (European version).
As soon as I press just a little bit the throttle pedal I've got this very annoying sound like a chirp. No matter speed or gear. If I press it more than a inch it stops.
I sent the car to the dealer and they couldn't find the problem after 2 days but changed the crankcase ventilation valve which reduced a little bit the problem but didn't solve completely.

I'll try the idea about the airbox.
Any more idea welcome