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looking for advice


JEBsFord

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I have an 1990 Bronco 2 with the 2.9. My cooling fan needs replacing, and I was hoping y'all could advise me whether to go with a regular automotive fan, an electric fan, or an flex fan. Thanks: Jim
 


JerryC

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I've gone back and forth on this issue.
Stock fan/clutch: reliable and moderately priced, eats some horsepower.

Electric: inexpensive version cost about same as replacing the stock fan/clutch. I would not consider an inexpensive e-fan to be reliable as a stock fan/clutch.
Expensive e-fan: reliable, expensive. Could track down a junkyard OEM fan and adapt it to get reliability and have lower cost.
E-fan may require alternator upgrade.

In the end what keeps me away from an e-fan is the thought of the 2.9's reputation for cracking cylinder heads when they overheat. Typically mechanical fans and clutches give you warning if you are watching for it where an typically e-fan fails all at once.

I got my replacement stock fan from LMC, it was the updated version. Got the clutch locally at auto parts store.

Flex fans eat horsepower like nobody's business, don't use one.

Tip: put a piece of cardboard between the fan and the radiator so if the fan slips it doesn't poke a hole in your radiator.
 

IIBRONCOS

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I live in a hot climate and the only fan that you can count on to work when the engine is running is a Flex Fan ( direct drive). I have had electric fans fail, and fan clutches fail, but never a Flex Fan. They pull max air at idle and the stainless steel blades flatten out at higher rpm's for less drag. I can idle at 105 degrees outside with the A/C on and the temp gauge stays normal.
 

deathbypsi

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Ford spends millions of dollars in research and testing on every vehicle it develops and they do alot of this at their Arizona Proving Grounds to make sure they can keep themselves cool.

If all the components are in good working condition there is nothing else out there that will out perform the stuff it came with. That said you need to do your part on making sure the rad is clean and clear inside AND out, fan shroud is on, clutch is working right,coolant is clean and full, thermostat is working and even making sure the tune up is good and ignition timing is set correctly.

Now thats not saying a electric fan or flex fan wont work. The problems I have seen is electric fan controllers that fail, fans that dont pull enough cfm, motors that burn out from water or dirt getting in them and crappy ways most people mount them that can damage the rad itself. And a flex fan will work but the noise and power robbing make them not a great option. They can rob as much as 30hp and on a motor that barely makes over 100hp thats a huge lose.

Just my $.02
 

wildbill23c

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I've had good luck with regular clutch driven fans, had to replace the one in my 88 Bronco 2 when I got it as it was bad, but they're easy to replace usually depending on how cramped the engine bay is in the vehicle. All that electric stuff is usually a hit and miss thing, I've seen far more electric fans fail for one reason or another so I'd rather have one bolted to the engine than an electric fan that might work.
 

IIBRONCOS

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Here's a vid of fan testing;
https://www.youtube.com/watch?v=ZXdLgaFXZzs

These guys do a series of videos like this, fun to watch and informative, IMHO.
I watched the video and it is interesting but does not show or give estimates on horsepower drop in a street driven vehicle. I would like to know the horsepower drop from idle, then accelerating moderately until the overdrive kicks in and the engine is at 1900 rpm's at 55 mph. That would help people make a better decision on how much to spend for their application.
 

JerryC

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I think you can look at the dyno curve for the fan and figure/guestimate some of that out.

The HP used by the fan is dependent upon rpm not engine load because the fan creates drag based upon rpm.

Looking at their graphs it seems to be about 2-3 HP at 3000rpm for any of them, that's not bad. But after that it starts getting ugly. If you are just driving easy any of them is fine, but when you need passing power or on-ramp speed the fixed and flex fans just kill your power.
 

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