O7 Caravan cold weather noise

When operating in cold weather (below freezing) at highway speeds, the car produces a whiney/buzzy sound when slowing down to park or get gas. the noise is very loud in the cabin, but hard to hear from the outside with the hood open. I assume the noise is there while driving but unheard over general road noise. Noise varies in pitch with engine rpm, and slowly dissipates as car sits at idle (warms up?). Noise modulates with turning of steering wheel, which makes me suspect PS pump, but could be anything attached to the serpentine belt. After being parked and I start it up again, no noise. Very curious, I apprecite any suggestions

The power steering fluid may be low. If the fluid is not low the next thing to check is the power steering reservoir, there is a screen inside to filter the fluid. When the screen becomes dirty/blocked the pump will be starved of fluid making the same sound as low fluid level would. This problem is most noticable when the fluid is cold, it is more difficult to pass through a partially blocked screen. A new reservoir is about $20.

Some of these vans had an issue with the high pressure power steering hose vibrating under load, which could be described as a “buzzy” sound (my observations have been more along the lines of a vibration in the steering column, but it could be the same thing). I don’t think there is a recall campaign, but I’m sure there’s a technical service bulletin concerning this. I think Chrysler made some new insulators or a redesigned high pressure hose to correct this. Have your mechanic check for a TSB about this. If this is what you determine is the cause of the issue, you could either have it repaired or live with it.

The only other “whining, buzzing” sound I can think of that is common in these vans is the solenoids in the transmission, which always buzz during downshifting/decelerating and is normal.