Hi all

I've got a 2004 R52. I am occasionally hearing a helicopter noise while running from under the hood. I recently replaced my PS fan, but I don't think that's it, as it is louder than i would expect the PS fan to be, and it sometimes starts just when i turn the car on (i don't think the PS fan runs that often...)

I would think it is the radiator fan, but it doesn't happen all the time. maybe 50% of the time, and there have definitely been times where i hear the rad fan going but no copter noise.

any other places to look?

thanks!

 

A loose fan shroud somewhere perhaps?

Could it be air conditioning related? Check to see if this only happens when the ac is on.

When you are hearing the noise, does it change with engine speed? Rev the engine and listen if the sound changes.

 

fan shroud actually sounds kinda clever. Perhaps!

I almost never use the AC. definitely not now.

It does not seem to change with engine speed.

Any other ideas?

thanks!

 

Usually, once the PS fan comes on, it stays on until you cut your engine off. Did you replace the fan with a refurbished unit? My PS fan has small dirt granules in it. The bad part is I can never completely get them out. Once in a great while, the granules get jammed at a point they make noise. But it's usually a higher pitch tone. I've sprayed mine down with WD-40 like it's going out of style, but it does not really make a difference (requires removing the fan and using a 12V power supply on the workbench).

The fan shroud is still a possibility, but only in the sense something is moving around inside the fan blade area. The object is shifting as you drive (remember putting a piece of paper on a fan in the house as a kid and letting the blades hit it?).

It's definitely not the water pump; speed is dependent on the supercharger spinning.

 

I don't have a super.

The helicopter noise sometimes comes on just as i start the car, which indicates to me that it is not the PS fan.

I actually haven't heard it in several days, so i think the above post is right, that something, perhaps the cowling, is hitting my main fan occasionally. Next time it happens, i'll look there.

 

Ah, not an S. Got it. I had to do a quick lookup for the R50 water pump. Since that's belt-driven, you can definitely take that out of the equation.

I can see a leaf or two occasionally getting into the cowl, but I do find it kind-of hard to believe something else would get in there and cause that kind of noise. Try using a flashlight to see inside the fan area in the evening or night. Sunlight makes it hard to do in the day.

Keep us posted.