Whistling sound upon cold start up

M302_IMOLA · Fri, Oct-08-2010, 06:12:41 PM

The past few mornings I have been hearing a faint whistling sound when I first start my car up (have to mute the radio to hear). The sound seems to last about 3-5 minutes and then disappears as the car warms up. The best way to describe the sound is it sounds like a very faint table saw...you know that high pitch sound you hear when you start up a table saw. The sound seems to get a little louder as the accelerator is pressed. Anybody else ever heard this before on their M? I can't help to be paranoid and think bad thoughts (i.e. vanos, cam gear bolts).

PenguinQX · Fri, Oct-08-2010, 07:42:22 PM

Yes, but on my car it's the supercharger

In all seriousness though, I never encountered this before when I was NA. Ever pop the hood to figure out where exactly it's coming from? Belts maybe? Bad belts can be noisey on startup and go silent after the engine warms up.

ShafferMD · Fri, Oct-08-2010, 08:08:27 PM

I would lean closer to a possible idle air intake or vacuum leak. Check around, it is likely that you have a crack or split in one of your lines. A small leak will not generate a code as the computer is able to correct the lean condition (if it is pre-MAF) or your not out of range yet on your O2 sensor readings (post-MAF). Our cars are getting older and the constant heat cycling of the engine compartment causes premature failure on the rubber connections in the air circuit.

My daughter's car ('03 325i) had the same condition but eventually threw a code for Bank1 / Bank2 lean.

Can be difficult to find, but easy to fix...

- Good Luck -

E-solo · Fri, Oct-08-2010, 09:45:40 PM

Im so glad you brought this up. I have 2 years experience with this whistling deal and I gave up on it. Here is some background on my experience with this:

Started with a faint whistle, which became more noticeable with time. It seemed to be louder when the weather was cold. Then it started happening while I was driving, so it sounded like canaries under my hood. It went away a bit during the summer, when the weather was warm. It comes back each winter when it gets cold out. Just started this week, as here in California is got a bit chilly.

I have taken the car to the dealer various time for this and had to show the dealer how to recreate the sound. They took apart my SMG and put it back together because the extended warranty would not pay for a repair. I decided to just leave it alone. The whistling went away for a while and comes back periodically. Not the dealer, not any indy shop has been able to tell me the problem.

BTW, I thought it was the SMG, but later realized it wasn't. Its obviously something else because my SMG is fine.

chris9 · Fri, Oct-08-2010, 09:49:28 PM

I had a similar sound that was prominent at start up but would go away as the car warmed up. Turned out to be the alternator, you may look into that.

MPOWERD · Fri, Oct-08-2010, 10:55:35 PM

I have heard this as well, comes and goes. My shop could not track it down either...

M302_IMOLA · Sat, Oct-09-2010, 03:25:05 PM

Quote:

Originally Posted by PenguinQX

Yes, but on my car it's the supercharger

In all seriousness though, I never encountered this before when I was NA. Ever pop the hood to figure out where exactly it's coming from? Belts maybe? Bad belts can be noisey on startup and go silent after the engine warms up.

Lol, I figured I would get some snide remarks regarding a supercharger. Good points on the belts, I will have to check them out.

Quote:

Originally Posted by ShafferMD

I would lean closer to a possible idle air intake or vacuum leak. Check around, it is likely that you have a crack or split in one of your lines. A small leak will not generate a code as the computer is able to correct the lean condition (if it is pre-MAF) or your not out of range yet on your O2 sensor readings (post-MAF). Our cars are getting older and the constant heat cycling of the engine compartment causes premature failure on the rubber connections in the air circuit.

My daughter's car ('03 325i) had the same condition but eventually threw a code for Bank1 / Bank2 lean.

Can be difficult to find, but easy to fix...

- Good Luck -

I did recently install a streamline panel air filter and Afe elbow...I have checked them out for leaks but didn't see any.

Quote:

Originally Posted by E-solo

Im so glad you brought this up. I have 2 years experience with this whistling deal and I gave up on it. Here is some background on my experience with this:

Started with a faint whistle, which became more noticeable with time. It seemed to be louder when the weather was cold. Then it started happening while I was driving, so it sounded like canaries under my hood. It went away a bit during the summer, when the weather was warm. It comes back each winter when it gets cold out. Just started this week, as here in California is got a bit chilly.

I have taken the car to the dealer various time for this and had to show the dealer how to recreate the sound. They took apart my SMG and put it back together because the extended warranty would not pay for a repair. I decided to just leave it alone. The whistling went away for a while and comes back periodically. Not the dealer, not any indy shop has been able to tell me the problem.

BTW, I thought it was the SMG, but later realized it wasn't. Its obviously something else because my SMG is fine.

Good info, thanks for sharing. It has been getting colder down south now which confirms your thoughts on it being louder during cooler weather. I swear the sound doesn't sound normal though...I have been loosing sleep over it.

Quote:

Originally Posted by chris9

I had a similar sound that was prominent at start up but would go away as the car warmed up. Turned out to be the alternator, you may look into that.

Could be...my car has a little over 105K miles and is on the original alternator as far as I know. At what mileage did yours go out?

Quote:

Originally Posted by M3_Modness

I have heard this as well, comes and goes. My shop could not track it down either...

Since you're in Texas and it has been getting cooler, have you been hearing it more lately?

FLBMWM3 · Sat, Oct-09-2010, 03:47:29 PM

I would lean towards the alternator or possibly the tensioners.

E46er4Life · Sat, Oct-09-2010, 04:12:31 PM

To me it sounds like it may be secondary air pump. Maybe a vid would help.

chris9 · Sat, Oct-09-2010, 11:30:05 PM

Quote:

Originally Posted by M302_IMOLA

Could be...my car has a little over 105K miles and is on the original alternator as far as I know. At what mileage did yours go out?

Car is a 2004, alternator went out at 95,000 miles, red battery light came on.
We were seeing 100+ outside temperatures which I believe expedited the failure.
Car is garaged and majority of miles were highway.

Fri, Oct-08-2010, 06:12:41 PM	#1
M302_IMOLA "Just Six" Join Date: Dec 2006 Posts: 2,398 In the garage: '02 BMW M3 Reputation: 0 Location: Chatt Town	Whistling sound upon cold start up The past few mornings I have been hearing a faint whistling sound when I first start my car up (have to mute the radio to hear). The sound seems to last about 3-5 minutes and then disappears as the car warms up. The best way to describe the sound is it sounds like a very faint table saw...you know that high pitch sound you hear when you start up a table saw. The sound seems to get a little louder as the accelerator is pressed. Anybody else ever heard this before on their M? I can't help to be paranoid and think bad thoughts (i.e. vanos, cam gear bolts). __________________ 02' IR/IR Current Mods: Painted front reflectors, matte black fender gills, carbon fiber roundels, Depo smoked corners, 19" Ruff Racing wheels wrapped in Hankook Ventus V12's (245/35F & 275/30R), Status Gruppe coilovers (7K/8K), RE RSM's, Powerflex RTAB's & FCAB's, DICE, CSL Rep Diffuser, CF Hamann Rep Lip, Magnaflow exhaust, Ebay headers, Streamline filter, Afe elbow, RPI scoops, ZHP knob, and EE LED tails. WTB: OEM Front strut bar, Evolve stage II tune, 4.10's, and CF CSL rep Bootlid

Fri, Oct-08-2010, 07:42:22 PM	#2
PenguinQX Registered User Join Date: Feb 2009 Posts: 477 Reputation: 0 Location: Philadelphia	Yes, but on my car it's the supercharger In all seriousness though, I never encountered this before when I was NA. Ever pop the hood to figure out where exactly it's coming from? Belts maybe? Bad belts can be noisey on startup and go silent after the engine warms up. __________________ 2004 M3 - Carbon Black AA Stage 2 Supercharger\|AA Coated Headers \|AA Exhaust\|FMIC\|Alcohol/Water Injection Kit\|etc.

Fri, Oct-08-2010, 08:08:27 PM	#3
ShafferMD M3 Enthusiast Join Date: Jun 2009 Posts: 611 In the garage: '93 BMW 325i '96 BMW 318 '03 BMW 325i '03 BMW M3 Reputation: 0	Air Leak I would lean closer to a possible idle air intake or vacuum leak. Check around, it is likely that you have a crack or split in one of your lines. A small leak will not generate a code as the computer is able to correct the lean condition (if it is pre-MAF) or your not out of range yet on your O2 sensor readings (post-MAF). Our cars are getting older and the constant heat cycling of the engine compartment causes premature failure on the rubber connections in the air circuit. My daughter's car ('03 325i) had the same condition but eventually threw a code for Bank1 / Bank2 lean. Can be difficult to find, but easy to fix... - Good Luck - __________________ 2003 6MT ///Carbonschwartz Metallic : Black Nappa : Premium Package : Cold Weather Package PERFORMANCE: 245/275 PS \|\| CDV Delete \|\| Clutch Stop \|\| BMW SSK \|\| RE RTAB's \|\| APPEARANCE: Invisibulbs \|\| AC Schnitzer Pedals \|\| Custom Toolkit w/ M3Forum Decal \|\| Painted Reflectors \|\| 55W Xenon Matched Fogs CONVENIENCE: Eurotray \|\| Dynavin V4 DVD/NAV Ask me anything about Powdercoating! PM me for Metric Clutch Stop sourcing

Fri, Oct-08-2010, 09:45:40 PM	#4
E-solo Registered User Join Date: May 2004 Posts: 1,834 Reputation: 0	Im so glad you brought this up. I have 2 years experience with this whistling deal and I gave up on it. Here is some background on my experience with this: Started with a faint whistle, which became more noticeable with time. It seemed to be louder when the weather was cold. Then it started happening while I was driving, so it sounded like canaries under my hood. It went away a bit during the summer, when the weather was warm. It comes back each winter when it gets cold out. Just started this week, as here in California is got a bit chilly. I have taken the car to the dealer various time for this and had to show the dealer how to recreate the sound. They took apart my SMG and put it back together because the extended warranty would not pay for a repair. I decided to just leave it alone. The whistling went away for a while and comes back periodically. Not the dealer, not any indy shop has been able to tell me the problem. BTW, I thought it was the SMG, but later realized it wasn't. Its obviously something else because my SMG is fine. __________________

Fri, Oct-08-2010, 10:55:35 PM	#6
MPOWERD Mod Hound! Join Date: Aug 2008 Posts: 10,724 In the garage: '03 BMW M3 Convertible Reputation: 0 Location: Texas	I have heard this as well, comes and goes. My shop could not track it down either... __________________ 2003.5 e46 ///M 3 TiAg Cabriolet SMG II... <> CSL Carbon Fiber Intake w/MAF, Brembo Gran Turismo, Euro Headers & Cats, K&N 69, Radenergie Carbon Fiber Strutbar <> EAS Carbon Fiber Kidney Grills, Carbon Fiber Fender Grills, SMG Carbon Fiber Paddles, Vorsteiner 2 Sided CF VCSL Boot <> EAS Slvr Carbon Fiber Interior Trim, Blk Carbon Fiber SMG Dome, Carbon Fiber Console, & Blk/Slvr Steering Wheel Trim <> EAS Carbon Fiber Engine Bay, Vorsteiner Carbon Fiber Valve Cover, RPI Intake Scoops, CarPC w/Nav/MP3/HD Radio/TV <> Eisenmann Race Exhaust, Supersprint X-Pipe with Resonator, Ekarbon 1/2 Carbon Fiber Diffuser, DEPO Smoked Corners <> 19x8.5 19x9.5 VMR V710s in HyperSilver, Painted Corner Reflectors, EAS Carbon Fiber Emblems, Carbon Fiber Hood Vent <> Slvr CF Pedals, OEM 2-Tone Hardtop, Windscreen, & Alarm, 6K Headlights & HID Fogs, Blk Carbon Fiber Headlight Trim

Fri, Oct-08-2010, 09:49:28 PM	#5
chris9 Registered User Join Date: Jun 2010 Posts: 4 Reputation: 0	I had a similar sound that was prominent at start up but would go away as the car warmed up. Turned out to be the alternator, you may look into that.

Sat, Oct-09-2010, 03:47:29 PM	#8
FLBMWM3 Registered User Join Date: Jun 2009 Posts: 151 Reputation: 0	I would lean towards the alternator or possibly the tensioners. __________________

Sat, Oct-09-2010, 04:12:31 PM	#9
E46er4Life Registered User Join Date: Sep 2008 Posts: 223 Reputation: 0	To me it sounds like it may be secondary air pump. Maybe a vid would help.

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