Hi I have a 2006 uplander that is making a loud siren like whistling noise at 40mph and up below 40 it stops and it seems to alternate from drivers side to passengers side in the front. Any ideas.

 

Interesting.....switches from side to side?

Have you looked at the front brake condition? Perhaps pads are used up and you're hearing metal on metal grinding?

Front wheel bearings? You're not a true Uplander owner if you haven't changed at least a couple of these.

Whistling makes me think of an air leak like a window molding while siren noise makes me think wheel related. Also check condition of accessory drive belt and tensioner. Can you duplicate the noise at a stop by increasing the speed of the engine in park?

Just some thoughts as to where to start.....

 

FINALLY figured out that the luggage rack on the top of the car was working loose. There was a pine tree "needle" stuck in the space. I'm guess that at certain speeds, the needle would vibrate against the top of the car.

Whatever... I removed the needle (haven't fixed the space yet) and the noise hasn't returned.

I hope you have a similar problem. Truth is, my 9-year old grandson noticed the needle first... guess when you get old, you don't notice some things.

Good luck.