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Discussion Starter · #1 ·
When my BMW is dead cold in the am, I get this weird "wee-wee-wee" noise. It sounds like it is coming from the front drivers side of the engine. The noise goes away after about a min.

I have tried belt dressing. Both belts look as though they are in good condition no cracks or breaks. Also, all the pulleys seem to turn normally.

Very Strange... Please help!!!!!!
 

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Secondary air pump kicks in for about a minute on cold starts.. that could be the culprit? It doesn't do anything vital, it just helps warm up your engine.
 

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Discussion Starter · #4 ·
you sure?

the secondary air pump is up on top at the back of the engine. Right? The sound seems to be coming from the belt side of the engine?
 

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its that round thing beside the engine looking like a coffee can, infront of the windscreen washer reservoir
 

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2003 M3 6MT Slicktop
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My secondary air pump when cold sounds like a small fog horn when cold. If you get a chirping or cricket sound on the drivers side belts, it's the tensioner pulleys(they have bearings). Both are common areas of sound.
 

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My secondary air pump when cold sounds like a small fog horn when cold. If you get a chirping or cricket sound on the drivers side belts, it's the tensioner pulleys(they have bearings). Both are common areas of sound.
that sounds like your oil separator not your air pump
 

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Discussion Starter · #10 ·
does anyone know what the big pulley directly below the alt. is?
it's located at the very bottom on the drivers side??? can't seem to figure out what it is?
 

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even though you can't really adjust alignment of the alternator and power steering pulleys, the sound only occurs on cold starts during the first minute or so. It's rubbing of the sides of the poly v belt in the grooves of the pulleys.
Even when you swap belts and tensioner pulleys, this noise will return very soon. We've had BMW install a brand new engine in one of our cars (M54) and even that car makes the cold start chirping noises.
Sometimes it helps to shim the bolts of either alternator or powersteering pump(more often than alternator) and by trial and error see if it helps. Or just live with it.
 

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2003 M3 6MT Slicktop
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that sounds like your oil separator not your air pump
+1
If your CCV is broken your car will make a "mooing" sound.
Maybe I'll check it again guys. There is a test to do to find out if it's your oil separator/CCV. Did that before and was good. Mine isn't that loud and I'm never in the cold like others that need the upgrade replacement like back East. 30 seconds maybe on the first start-up of the day. Also, I can put my hand on the pump and hear it change tone.
 

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Honestly my 330 has made that same cold start sound for over 5 years.
 

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If it's an intermittent sound, like the "wee wee wee" you describe, wouldn't it likely be something that's turning, like the belts or pulleys, or water pump, rather than something that's vacuum operated? Just a thought.
 

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2003 M3 6MT Slicktop
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^yes it's hard to diagnose since the OP never answered my question. If it's a chirping sound like a cricket that is the bearings in the tension belt pulley. These are known wear items and after they heat up the sound often goes away. Other times if the hydraulic shock in the tensioner assembly goes, it doesn't have enough tension and cause the sounds too. Both are on the front of the driver's side and deal within the belt system.
 
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