I have noticed my Grand Caravan making a strange noise lately. It almost sounds like the mid 80s fords power steering system, but it gets more noticeable with increased rpm. I have a 3.3L automatic.
Replaced the serpentine belt last year, and did a tranny filter/fluid change.

Anybody have any ideas?

 

...and you checked the power steering fluid?

 

Yep. Checked the tranny juice, too. It stops when the A/C is off. I am thinking my compressor is going again. Wondering if anyone else had a similar experience.

 

Well,

My Wife's T & C use to make a slight hissing sound when the A/C was on. Since my Wife ALWAYS used the recurculate swithc, she never knew that the condenser had a pin leak untill the car didn't seem to get a cold as it should.

Thankfully, it was still under warranty!

I'd check the A/C....

 

A bad H-valve can cause the noise you describe.