My other wise flawless '02 MCS has an intermittent whistle coming from the engine bay. It occurs only under power and in all gears and at all speeds whether accelerating or cruising. It is a loud medium to high pitch whistle. Slip it into neutral and it disappears, rev the engine in neutral and it's not there. I read of one occurance where someone had a whistle where the rubber at the supercharger plenum had a hole in it and caused the whistle. When the dealer replaced the water pump o-ring an inspection of the supercharger showed no problems.
Also, temperature seems to not matter. It's happened in 15 degree weather and 35 degree weather.
Anyone else heard of this or have any ideas?

 

So it only does it when you're moving?

They checked the green supercharger to intake gasket then?

Spray some silicone on the belt at the side and see if it stops.

Send me more info, and I'll try to help you out.

Randy

 

Thanks Randy. I've emailed you with more information. BTW, the red stress bar I got from you on 1/31/03 looks fantastic. Thanks.

Steve B.

 

ok so clarify this: This is a whistling besides the usual supercharger whine? How is the acoustic spectra and harmonics different from "correct" to what your hearing?

 

Yeah, this is definately not the usual whine from the supercharger. It's a relatively high pitch tone that doesn't waver in pitch but does change in volume a bit. Ever blow across the top of a beer bottle and get that low pitch tone? Well, take the beer bottle and stick it out the car window at 70 mph and you would have that steady monotone whistle from the bottle. Now take that low pitch and bring it up to the highest note on the scale and that's what it is. It's maddening. About 7 miles into a trip up to Boston yesterday it stopped completely, then it came back again with a vengeance at 45 miles and lasted another 30 miles until the car was stopped.
This morning it was fine for the first 20 miles or so and then it came back!
It's not a slipping belt. After email discussion with Randy BMC the most likely culprits are: 1. supercharger intake gasket. or 2. gear box. Will have to get it to the dealer this coming week.

 

CCM,

I don't think I ever verified if the noise will occur stationary, but with the rpm up. If it doesn't occur stationary, I would think it's gearbox related.

If it does happen stationary, spray some silicone down into the gasket area and see if the sound stops for a second. That would be the indicator that it is, in fact, the gasket.

Let me know what you find out.

Randy

 

I beleive I have this whistle but I only hear it occasionally.

 

Past two days absolutely no noise or whistle! Randy, it doesn't happen when revving engine and car is stationary. Only happens while driving and under power. If I let off the gas it stops almost immediately. There is a slight second or two where you can hear it after you get off the accelerator....sort of like it's winding down. If the clutch peddle is depressed the noise stops immediately. More and more, I'm thinking gear box :???: