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Auxillary cooling question

littlejimmythatcould

littlejimmythatcould

1/2 ton status
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Feb 6, 2006
Posts
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Location
Clovis, NM
My motor has a stock 190* thermostat in it but if the weather temperature outside gets above 80* the motor over heats by 10*-15* at idle and stop and go driving (I have no problems on the high way). So my question is: how many people run auxillary fans and how big of one should I run? I bought a 14" fan that flows 1250 cfm with only 11 amps draw to run when I'm putting around. I was debating on running 2 of those fans and ditch the stock clutch fan. But I was wondering if 2500 cfms ( about 2100 cfms actually through the radiator) would be enough to cool the motor on it's own. Plus I might be able to pick up a few extra ponies. It's fixin to get warmer here in a few days so I'd lilke to get everything on there hopefully next weekend. Also, do I need my stock fan shroud? It's cracked and broke where the mounting bolts go and sort of just floating in there. I had a buddy that had that happen on a mustang and it bent one of his fan blades and shredding his radiator. So can I go without it? Especially if I ran dual auxillary fans and the stock clutch fan. Any thoughts or comments would be greatly appreciated.:bow:
 
80 is a little cool to be overheating. Before you get into the electric fan thing, I'd make sure your radiator isn't all rusted inside and you have a functioning fan shroud. You should definitely have a well fitting fan shroud for stock setups, especially in the southwest. I could see it overheating at 95 outside in stop and go but not at 80. Check your other stuff and make sure it's all working OK before you add something new to the mix. Easier to eliminate problems that way.

That said, there's a lot of data on electric fans in search. Look for windstar fan.
 
It's a new radiator and my fan shroud fits pretty good it's a little loose but still provides good sealing around the edges. And I take that back... it's probably closer to 85*to 90*. Maybe it's not over heating... I've been reading on a few threads and some people say there's runs at 220* also. I just thought that to be a little too hot since I'm running a 190* thermostat. What does yours run at?
 
Runs probably 200, maybe 210 for short periods, when it's really hot out and under load. I sat in bumper to bumper last summer in 105 degree heat in August on the freeway in L.A. and the truck ran really cool - definitely not much over 200. I have a 4 core rad, HD fan clutch, tightly fitting shroud and a tranny cooler.

What almost killed the truck sitting on that freeway was damn vapor lock.
 
I'd ditch any thoughts of running a mechanical and electric fan, and I'd also say that if you want electric, just go with the windstar setup. It's a proven piece for our rigs, and there are plenty of them out there.

The stock fan alone should be enough to keep it cool, sounds to me like a bad fan clutch. (cool on freeway, hot at idle) You don't lose much at all in power with a clutch fan, it's less than 5HP from the tests I've seen. Electric fans will give that back, but only when they aren't running...you just transfer the load from the water pump (clutch fan) to the alternator (electric fan) when they are on.

When the electrics come on, the initial draw on the engine is quite impressive...enough to kill my 350 if they come on at the same the engine is just starting to turn over on it's own.
 
I might try that (replacing the clutch fan). It was one of the only things I didn't replace on my motor when I rebuilt it. And amp draw is no big deal because I splurged and got the powermaster 140 amp alternator. So I've got about 75 amps to play with. What would go bad with my stock fan? I painted it to match my motor. Hmmmm... I'm about to try the shotgun method... throw parts at the problem till its fixed. Replace the clutch fan and add an auxillary electric fan with a "just in case" switch.
 
The fan clutch (from what I've experienced) leak the fluid out, so no lockup, and at some point will also come loose from the shaft as they fail. The spring on the front of them is thermostatic, they can come loose, break, etc.

You don't want to get a cheap fan clutch, make sure it's got the spring. Some of the aftermarket junk doesn't have it. There are stock applications for a heavy duty fan clutch, but I can't recall what some of the apps were. May have been posted on the board before.

You can usually pop the hood on a "cold" engine, start it, and listen for the roar (and usually feel the air moving) as the fan kicks in, then unlocks.
 
A very few trucks (can't recall which combos exactly) got "solid" fans with no clutch.

Does yours even have a clutch or has it been replaced? They can stay locked up, and I've heard of people tightening the spring to change the activation temp, so anything is possible.

Now the stock clutch fan will still spin, that doesn't mean it's actually locked up. It will never stop spinning when the engine is running.
 
When the fan clutch is engaged, you'll definitely hear the roar of the fan. I put a new heavy duty one in my '90 Suburban last fall. It sounds like a hurricane under the hood when the clutch is engaged. :cool1:
 
I must have a bad clutch then or something. I guess I'm not really sure of what I'm listening for. It has a clutch on the front of it and the fan spins with the motor. Hmmmmm.... I'll try getting a new clutch on it this weekend(wife permitting) and see what happens.
 
The fan will always spin, just from the fluid coupling of the clutch, even when in "slip" mode. But when the clutch engages, THEN the fan is spinning at the same speed as the water pump and you'll quite noticeably hear the noise of air rushing over the fan. :) The difference between on and off is huge.
 
Alright, cool. I'll check out gettng new clutch this weekend but I'll still hold on to the 1250 cfm electric fan just in case. Who knows it might still come inhandy. Especially when it gets 105* or more here in new mexico. I have also pin pointed that my motor migth be "loading up". I just put a new carb on it and I'm still in the process of tuning it.
 
If everything is working right, you won't need the electric fan. I had an '87 K5 when I lived in Houston and it never got too hot, even with the a/c blasting on high. :)
 
I've got 2-65 AC. 2 windows down going 65 miles an hour or I just take the top off. Hey, I sure do appreciate everyone's input thanks for yall's posts.:bow:
 
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