ddloyd,

Sorry I'm just now getting back to this. I work from home and don't drive that much these days so today was the first opportunity I had to test it. The weather at the time of the test was about 25 F and the car had been garaged. The temp meter was pegged on cold and stayed that way for about 2 miles. At the first stop sign I came to I turned the heater to fan setting 4, cranked the heat dial to the max, and floored it. It did not make any noise even with the temp still pegged at C. At the next stop sign I repeated the test and detected an almost imperceptible difference in sound. It was a slight drop in speed and if I had the radio on I would have completely missed it. So I would say mine is not doing what yours is doing.

After thinking about this more and more it does seem that I recall this happening in a reverse situation. In the heat of an Oklahoma summer (100+ temps) with the A/C going full blast the fan speed did seem to fluctuate depending on the rate of acceleration. It seemed to mostly happen with the 4 cylinder cars I owned though. That would make more sense because of the A/C compressor which taps the electrical system.

I'd definitely have the dealer check it out if it's a big difference in speed. It is better to be safe than sorry I guess.

MWCline