Cooling Fan Operation

[Eric91Z]

I was just wondering if anyone has some brilliant insight in to the operation of the cooling fans on an '04 Marauder? I always thought that the cooling fans would come on at a certain temp and then turn back off once it cools down to a certain temp.

I have been noticing that on my commute to work (about 50 miles one way) which is mostly highway/interstate, that if I get on it some during the trip that when I finally exit and am sitting at the first stop light I can hear the cooling fan running and it is still running when I park at work. I can turn the car off and back on and it is no longer running. Kind of like once it comes on it will not shut itself back off.

I have had this happy some if having a little fun around town or on the way home (we kind of live out in the country) and get home and hear the cooling fan running. Turn the car off the fan turns off. Turn car back on and the fan is no longer running or doesn't come back on until getting on it again.

I do have a newer XCal2 from Lidio and not sure if there is something built in to the tuning that causes this or something else going on? The car never seems to get too hot according to the temp gauge and runs wonderfully. Just wondering about these cooling fans.

Any thoughts?

[MitchB]

There is a desired coolant temp setting in your PCM. Fan speed is controlled by pulse width modulation depending on what your coolant temp is.

http://server6.theimagehosting.com/image.php?img=Temp%20copy.jpg

Your fan could be running at a slow speed and you might not hear it. Anyway, the PCM will try to adjust the fan speed so you always stay at the desired coolant temp. Your fan operation sounds normal to me.

Mitch

[DEFYANT]

Also if your defroster or a/c is on, the fan comes on.

[Todd]

I did some testing on mine to determine when the computer turned the fan on and off because I want to use the factory control module (little silver box on fan shroud) to conrol my aftermarket fans.

The engine has to be running to kick the fans on. So if you just turned the key back on then it wouldnt have started back up. But if you cranked it back up and the fan still wasnt on then I dont know. (have to admit I didnt try a/c on with just key on. Dont know if that would trigger fan without engine running.)

As said already, the a/c or defroster will also kick the fan on aNd keep it on till that accessory is turned off.

[Eric91Z]

The times I have turned the car off and back on I have actually restarted it and let it sit idling for a little bit to see if the fans would come back on and they do not - at least not at a speed at which I can hear before shutting the car off in the first place.

Not sure what the deal is or if it is normal. And I didn't know the speeds would constantly run but at varying speeds to keep the temp. I thought it was just set on and off temps.

[rayjay]

IIRC, Lidio's tune specs turn the fan on at a lower water temp than stock.

[Eric91Z]

IIRC, Lidio's tune specs turn the fan on at a lower water temp than stock.

If that is the case, I guess it could help explain why this happens. I didn't get the tune until a month or more after I got the car. I got the car early last September and had the month or so to drive, enjoy, and get on it with the factory tuning and don't remember this happening. Could be a safety thing to help keep it running cooling with the timing advanced, etc. that he does with the tuning. And it did seem to happen with both the 91 octance tune I have been running since November and now again with the 93 octane tune in there.