Engine Fan

[TSimpler]

So as all go stories go
No $h!t there I was... Driving from Roswell to Pecos. The outside temp is around 110 and my engine fan does not come on and I get 19.5 MPG.

On the way back the temp is 105 and the engine fan will not turn off. I get 16.7 MPG.

WTF!!! I drove the same speed and the temp was lower.

Thanks
Trent

[mdadgar]

Originally posted by TSimpler:

On the way back the temp is 105 and the engine fan will not turn off. I get 16.7 MPG.

WTF!!! I drove the same speed and the temp was lower.
I find that once the fan comes on the computer really doesn't want to turn it off again unless it sees dramatically lower engine load for some period of time.

It's kind of like how when running on the highway towing on cruise control and you hit an uphill grade, the Allison downshifts and then when the road flattens out it won't let go of the lower gear until you "convince" it by canceling cruise and coasting for a bit.

Very, very annoying.

- Mark

[OC_DMAX]

The engine computer does not control the fan. The fan is measuring the temp of the air coming from the radiator stack. When a certain temp is encountered, it engages automatically.

[Ofbmicsafety]

Is there a good electrical fan system out there that could replace our old antiquated system? I know that F**d had an aftermarket one when I drove a 7.3. My 05 GMC 1500 with the 4.3 has a dual electrical fan system on it. But there sits my Duramax with fan and fan belt. Why can't the Duramax be as up to date?

[TSimpler]

Is there a way to "trick" the mechanical fan in to disengaging. I had no problem with the engine getting hot.

Trent

[Kennedy]

If the fan engaged it was for a reason. Whether it was coolant, trans, intercooler or AC generated heat, there was a need for more air flow through the radiator as the temp of the air at the fan clutch had reached the cut in temp...

[Jim Brzozowski]

From Roswell to Pecos is down hill.