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FAN CHANGES SPEED

Posted: Tue Nov 03, 2009 10:37 am
by raddoris
Ok not sure if this is normal,never noticed it before.If I have the fan blower on high and am sitting at the lights (idle/stopped) the fan seems to be working ok. As soon as you hit the gas to get moving the fan speed increases slightly. In both conditions the speed is constant (just a slight bit faster when the car is moving)Now I know the fan speed should not be related to the speed of the car. Seems like for some reason the fan is not getting all the required power or something.Any ideas/suggestions?thanks in advance.

Re: FAN CHANGES SPEED (raddoris)

Posted: Tue Nov 03, 2009 11:02 am
by Water boy
Could be the change in voltage from the alternator from idle RPM to above idle as in driving RPM.

Posted: Tue Nov 03, 2009 11:47 am
by j42.snyder
Yes - completely normal. At idle the alternator may have trouble keeping the voltage right up, depending on the electrical load at the time. Once off idle, it's got much more ability to generate the power needed.I think virtually every car I've owned has done this. The oldest ones were most noticeable - as the alternators were much lower output. If the A/C is engaged this will be worse as well - as it's also running a cooling fan on the radiator.John

Re: FAN CHANGES SPEED

Posted: Mon Jan 07, 2019 12:46 pm
by o2ej
Glad to have found this post. With a new alternator, blower and resistor, I am hearing the blower speed increase once the car is moving. Thanks!