Have F250, seeking better mileage

[Frank Lee]

Originally Posted by slowmover

Electric fans just shift the exact same burden to the electrical system. Are you willing to put it to a higher strain? Might gain a little in solo driving, but the question always exists as to whether an aftermarket set of e-fans is capable of the same duty rating as the mechanical fan.

No, they don't shift the exact same burden. The mechanical fans, even clutched or flex, are always spinning thus are always a parasitic loss especially at above idle rpms.

In my experience (several years with NO fan in the F150, including towing) the only time the fan is needed is when the vehicle is going too slowly to move air past the radiator- for example waiting at stoplights or extended parking lot maneuvering- even moreso if the A/C is on. I do completely remove my winter front when it's warmer out.

[slowmover]

"Modern" mechanical fans can have electromagnetic clutches (if we misunderstnad each other here). The "free wheel" is different.

The amperage draw for an electrically-driven pair of fans to cool a hard-working 1T truck radiator is huge. A bigger alternator is called for (and the re-size has to have a load reserve margin increse as well). 140A to 220A would be about right, assuming one can find an ambulance-package factory alternator.

Even with an older style mechanical clutch the trade-off may not be worthwhile. The HP draw may be similar, and one is hard-loadng the electrical to do it.

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[Frank Lee]

Admittedly my experience is with a 1/2 ton with a 302, and my car. Still, I wouldn't expect a cooling fan to need to work hard, if at all, when the vehicle is moving. I've adapted to the fan delete by being more careful to avoid hot stationary idling. That might be a bit much for campground maneuvering but I'd be surprised if an e-fan couldn't handle it w/o any alternator upgrades.

[slowmover]

Originally Posted by Frank Lee

Admittedly my experience is with a 1/2 ton with a 302, and my car. Still, I wouldn't expect a cooling fan to need to work hard, if at all, when the vehicle is moving. I've adapted to the fan delete by being more careful to avoid hot stationary idling. That might be a bit much for campground maneuvering but I'd be surprised if an e-fan couldn't handle it w/o any alternator upgrades.

I agree with your statements on this question from a lifetime of experience with V8's. But things are different since the Big Three finally replaced motors designed in the 1950's and 1960's by before 2005.

I have not owned a 1/2T of the "modern" era and can't speak to them specifically, either.

I would add to it that the heat rejection load needed in the southern US is not to be trifled with. I take it that if one has a 1/2T one needs one (eventually, towing & payload; my agreements with your sentiments on soccer daddies notwithstanding). Thus I would search out someone who has an aftermarket electric fan kit and has put thousands of miles of HD usage on it -- climate, terrain and use similar to ones own -- before considering buying one. An automatic tramsmission makes this, IMO, mandatory. Add A/C to that in stop/go traffic . . . .

HD fan use is limited over the percentage of miles of the vehicle. But the use itself may be from 1/2-hr to a couple of hours at a time. Nothing I'd be willing to trifle with no matter the engine type or vehicle spec or brand.

I'd imagine a retrofit to an older vehcle of a truck-specific fan/shroud/electrical package may be a good one for someone somewhere at some time.

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[Frank Lee]

I've read that Taurus fans are pretty strong; if I ever put an e-fan on the F150 it'll probably be one of those... mainly because I already have them sitting in my spare parts stash.

[cRiPpLe_rOoStEr]

Originally Posted by Frank Lee

I wouldn't expect a cooling fan to need to work hard, if at all, when the vehicle is moving. I've adapted to the fan delete by being more careful to avoid hot stationary idling.

No wonder many motorcycles don't have fans. Well, avoiding idling at all increases fuel savings

[Frank Lee]

Well... not that I do much of any idling anyway; I should have said low speed operations.

[cRiPpLe_rOoStEr]

Originally Posted by Frank Lee

I should have said low speed operations.

That's a critical condition for overheating, no wonder I see more cars overheating in a traffic jam than in an open road

[oil pan 4]

Originally Posted by Frank Lee

In my experience (several years with NO fan in the F150, including towing) the only time the fan is needed is when the vehicle is going too slowly to move air past the radiator- for example waiting at stoplights or extended parking lot maneuvering- even moreso if the A/C is on. I do completely remove my winter front when it's warmer out.

This is what I have found too.
(I don't have A/C and cant comment on its use)
The Fans stay off about 99% of the time when vehicle speed is below 35mph and stay off all the time above 35mph.

[slowmover]

Originally Posted by oil pan 4

This is what I have found too.
(I don't have A/C and cant comment on its use)
The Fans stay off about 99% of the time when vehicle speed is below 35mph and stay off all the time above 35mph.

Except when pulling a grade heavily-loaded or towiing. Putting the truck to work as designed. Higher rpms and throttle fully open will find any weaknesses in the cooling system. Might be at WOT in 2nd, 3rd or other than top gear for 20-minutes or longer.

The engine fan (shroud, etc) had better be up to snuff. The hotter the weather, the worse it is.

But it is NOT hot weather only. The need to shed heat rapidly can surprise you on some cooler days.

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