very loud squealing but not power steering??

[lanman_4]

I have a 2006 M35X approx. 82,000 miles on it.
It has started to make a very loud squealing sound when starting up cold. Takes about 30 seconds before the noise stops. I thought it was the power steering pump but when I took it for a drive (my daughter drives it) the sound only came back occasionally and when I put it back in the garage I did crank the wheel back and forth and it didn't scream. When revving the engine a bit it did make the noise but only a bit.
I called a dealer a few days ago thinking it was the PS pump, they told me it was $1250 for the pump!!!!! and a couple hours labor.
I'm hoping I'm right it isn't the pump,,, anyone have any idea what would be making that noise if not the PS pump?
Thanks for any help.

[retho78]

My guess, the drive belt(s) is going bad and probably change belt tensioner(s) while at it.

[EdBwoy]

I would also look at the drive belts as mentioned above. Check to see that they're not dry and cracked.
Then check the tension on the belts as loose belts could squeal as well.

[Ilya]

Agree on belts.

Funny story: I changed the belts on my 2007 M35x and couldn't get the tension right so it was squealing. I went to the dealer to have them properly tightened as I gave up and I walked out with a 2011 M56x instead of proper sounding belts. Hahah. Gave me an offer for my car I couldn't refuse.

[EdBwoy]

Hahaha, talk about being done dealing with that mess! I don't blame you, everyone likes an upgrade!

Ever since I got my y34 I anyways wondered if you could retrofit auto tensioners to the v6 engines. They are not only convenient, but also could potentially increase belt and pulley bearing life.

[steve_c]

Could be a 1-2 punch......
Cold weather starting puts more demand on the battery. At startup, alternator output needs might be higher than usual to get the battery back up to snuff. Increased alternator output puts a load on the engine, more drag on belts. If belts are a tad on the loose side, they will squeal under these conditions!

What I do is take silicone spray lubricant and spray down the belts & pulleys to see if the noise goes away. If so, most likely needs belt tightening. As already mentioned in previous replies....How do the belts look? Any signs of cracking/deterioration on the ribbed side (side that comes into contact with the pulleys)?

[MaxBolus]

One more item to check- the idler pulley. Mine did that for about 2 weeks before it seized.

[BlackCat81]

Belt squeal. Factory belts tend to stretch over time and thick fluid in cold weather demands more stress on the accessory drive. Just throw a set of belts on it and call it a day.

[TDot]

Mine (assuming the belts as of now) started squealing like a stuck pig last night. Shocked the hell out of me because there was no lead up, not a peep prior to last night. All of a sudden I start the car to go home, turn the wheel and thought a hog was being murdered under the car! What baffled me was it only happens when I'm standing still and turning the wheel. Hopefully I can get a chance to tighten it up this coming week.