Fan come on to much?

[jeepwidow]

I’ve noticed my fan comes on quite a lot. I have no idea if these trucks are supposed to be this way or not. First time ever was climbing a descent grade towing about 7k or so. I hear it come on for about 20 seconds I’d say, then it goes off for a little while, then does it again. It was a long hill.

Anyway, I noticed it yesterday when climbing a steeper hill, but all I had was a quad in the back, and two other people. It was in the 80's but that’s not really that hot considering these trucks drive all over the country where its much hotter.

Should I take it to the dealer? I’ve put it off cause the only time I'm on steep hills like that is when I'm towing the 7k and I figured it was normal, but this quad thing bothered me.

[AutoJim]

There are several inputs into the fan control: coolant temp, intake manifold temp (for CAC performance monitoring), AC demand, and auto trans fluid temp. Any one of those could trigger the fan to come on. I think there's an issue with the coolant temp sender and gauge doing some weird erratic stuff that may be a contributor -- if the sender says the coolant is hot, the fan will engage, for instance.

Might want to have that checked out -- but in general, if it needs the fan, you're gonna know it by the noise. Not much to do about that given it's a 26" diameter fan with about a 3" pitch. It moves an awful lot of air when it's engaged and the engine is over roughly 2K RPM, and that makes noise.

Here's the real kicker: anything you do to quiet it down will cut the airflow, and the way the Visctronic fan drive is setup, it really should only be kicking in when you really *need* the airflow.

All bets are off if you have the snowplow package, though. I understand those have a "conventional" air-sensed thermostatic fan drive, not the Visctronic, and, due to CAC performance requirements for emissions control, I would imagine it's got a very low cut-in temperature, which will tend to engage the fan when you don't really think it needs it. Something the Visctronic fixes, but there's apparently some issue with the low disengaged speed of the Visctronic, and funky airflow patterns when running with a plow blade in the up position that could actually cause the fan to turn backwards, rendering the drive unable to engage at all. The thermostatic fan drive has a higher disengaged speed (due to more internal drag) and solves that problem at the cost of the other problem.

[bigwhite1]

mine came on a lot as well, untill i took the bug screen off, now it hardly ever comes on, only steep grades. i tow 12k.

[AutoJim]

[ QUOTE ]
mine came on a lot as well, untill i took the bug screen off, now it hardly ever comes on, only steep grades. i tow 12k.

[/ QUOTE ]

Bing!Bing!Bing!Bing!Bing! We have a winner!

Obstruct airflow, run hotter, require more fan operation. Remove obstruction, run cooler, less fan operation.

So if you have one of those fancy metal cutout grille appliques (tribal flames, funky patterns, whathaveyou) and you're running hot, don't blame Ford...

[DSI]

with 60k miles, i've heard my fan a dozen times or so, usually towing either an enclosed trailer, or a 2 car flat deck. now going to phoenix last weekend, with only a single car flat deck, my fan would come on/off constantly, bout 10-15sec on, and the same off for 20-30 miles at a time. i've got the stock grille, no restrictions that weren't there from ford... but i did just get it back from the dealer the day i left, is it possible that i ended up with a new flash that might have something to do with it? since my mileage went up, and so did power, and coolant stopped blowing out. [img]/ubbthreads/images/graemlins/shrug.gif[/img]