Disconnect 9-blade fan?

[DennisG01]

Another thread got me thinking about my fan. I just ran around for about 15 minutes and temps never went over 190* (according to my ScanGaugeII). When I got back in the driveway (temp at 186*), I popped the hood and saw the fan was spinning. I kicked on the high idle switch and the temp got down to 182* and the fan was still running.

Right now, I'm not towing - is there an easy way to "delete" the fan? Or, maybe a better way to say it is "deactivate" it so it does not come on. By easy, I mean, a way that I can easily "reactivate" it out on the road if I need to. I'm curious to see what the temps do.

I have JK's HD clutch and a 4-bolt fan.

I suppose I could take the fan off, but was hoping for something easier (although that really isn't that hard, either). I'm thinking that there isn't - but just wanted to check to see if I was overlooking something.

 

[great white]

Viscous fans are always spinning. There's always some drag in the mechanism.

They just aren't pulling as much air and extracting as much Hp (thus, MPG) from the engine until they're locked up by temperature.

It's a tiny bit more involved than that, but that's it in a nutshell.

There's no real way to disable it, it's essentially a mechanical system.

The other options are electric fans (a problem if you tow, from what I'm told) or adapting a hummer (I think it's a hummer) style electric lockup style clutch fan...

 

[DennisG01]

OK, so it's just sort of "free wheelin"? That makes sense.

Yeah, years ago I looked into electrics and they didn't pull anywhere near enough air as compared to the stock fan.

Maybe I'll just take it off and see what happens. As long as I watch the temps, there shouldn't be a problem. I'm just curious if there's a substantial MPG savings. It's probably going to be one of those things that's barely noticeable, if that.

 

[great white]

OK, so it's just sort of "free wheelin"? That makes sense.

sort of, this guys does a decent job in laymans terms and even has a gif drawing:

http://www.aaroncake.net/rx-7/efanmyth.htm

here's one that's a little hard to read, but has animated gifs!

http://www.gwagen.de/html/english/Viscol.html

I'm just curious if there's a substantial MPG savings. It's probably going to be one of those things that's barely noticeable, if that.

I'll guess option 2.

Maybe a mpg or so...

 

[Edzzed]

You would get some cooling just by wind when driving but when you get in stop and go traffic you'll want the fan as wind alone won't do it. I have seen electric clutch fans which is something you may want to look into. they have pto electric clutch stuff and you just might need to find some way to adapt it to your truck. http://www.smarter.com/se--qq-warner%2Belectric%2Bclutch.html Me i would just pay to have the proper stuff on the truck. I don't believe an electric only fan would help a whole lot when you are towing in the hills. maybe a guy could setup 3 or 4 radiators in series so the water is a lot cooler by the time it gets back into the engine. many years ago I duct taped up a car radiator to a fan in the house and used a garden hose to fill the radiator from the bottom and had another hose to drain the radiator from the top to the outside of the house and stuck it in my bedroom window. I called it poor mans air conditioning and it worked. maybe not as well as genuine a/c but enough that my room was not hot when trying to sleep.

 

[NVW]

You would get some cooling just by wind when driving but when you get in stop and go traffic you'll want the fan as wind alone won't do it. I have seen electric clutch fans which is something you may want to look into. they have pto electric clutch stuff and you just might need to find some way to adapt it to your truck. http://www.smarter.com/se--qq-warner%2Belectric%2Bclutch.html Me i would just pay to have the proper stuff on the truck. I don't believe an electric only fan would help a whole lot when you are towing in the hills. maybe a guy could setup 3 or 4 radiators in series so the water is a lot cooler by the time it gets back into the engine. many years ago I duct taped up a car radiator to a fan in the house and used a garden hose to fill the radiator from the bottom and had another hose to drain the radiator from the top to the outside of the house and stuck it in my bedroom window. I called it poor mans air conditioning and it worked. maybe not as well as genuine a/c but enough that my room was not hot when trying to sleep.

Kinda "Redneck" Ed:hihi:

I've used tinfoil, plastic garbage bags taped to a window, and even my grain truck parked in front of it to block the sun.

 

[DennisG01]

You guys are pretty ingenius! :thumbsup:

It's unlikely I'd buy an electric fan as, assuming there would only be a very minor gain in MPG, it would take an awful long time to recoup the payback. Besides, I'd have to put the stock fan on during Spring, Summer and Fall when I'm towing.

Do you think, with ambient temps under 60*, there would still be a possibility of overheating in stop-n-go traffic?

 

[Edzzed]

Kinda "Redneck" Ed:hihi:

Yeah but that was in my early days. Water coming out of the taps here on cold is 41 degrees in winter rising to 60 ish in summer. Right now tap water cold is 43 degrees so it's coming up. Even wind blowing over a radiator that is 60 degrees in summer has a cooling effect. I don't know how hot it gets in Castor but here in Vancouver we once set a record with 97 degrees. Yeah, I can imagine people down south laugh at 97. I suspect it's a different kind of heat.

 

[guybb3]

I disconnected my mechanical fan two or three winters in a row now. Just watch the temps and you'll be ok. Stop and go traffic and you have to turn all the heaters on (front and back) to keep the engine temp down. And you're right, MAYBE a 1/2 mpg difference.

 

[DennisG01]

I disconnected my mechanical fan two or three winters in a row now. Just watch the temps and you'll be ok. Stop and go traffic and you have to turn all the heaters on (front and back) to keep the engine temp down. And you're right, MAYBE a 1/2 mpg difference.

That's good enough for me. I was going to do it mainly to experiment. Me "guessing" that it wouldn't save much MPG is just that... a guess. I like to rely on real world experiences or, at the least, be able to comfortably transfer knowledge from one experience to another. In the sports world we call it "skill transfer". For example, if you're good at a tennis serve, you'll learn an overhead volleyball serve very quickly (same basic form).

The only one that I could transfer the fan issue from is a boating experience. But it doesn't completely transfer well. I once lost a power steering pump (plastic pulley disintegrated). I couldn't get a rope tied onto the remaining pulleys tight enough to stay on for more than a minute. So, I had my friend stay back by the engine and just turn the circ pump pulley by hand. It probably didn't do much, but we were able to limp back to the ramp well enough. 'Course, it didn't hurt that our "coolant" was a constant 72*!

GW: Thanks for those links - they were very helpful.

 

[Burning oil]

You would get some cooling just by wind when driving but when you get in stop and go traffic you'll want the fan as wind alone won't do it. I have seen electric clutch fans which is something you may want to look into. they have pto electric clutch stuff and you just might need to find some way to adapt it to your truck. http://www.smarter.com/se--qq-warner%2Belectric%2Bclutch.html Me i would just pay to have the proper stuff on the truck. I don't believe an electric only fan would help a whole lot when you are towing in the hills. maybe a guy could setup 3 or 4 radiators in series so the water is a lot cooler by the time it gets back into the engine. many years ago I duct taped up a car radiator to a fan in the house and used a garden hose to fill the radiator from the bottom and had another hose to drain the radiator from the top to the outside of the house and stuck it in my bedroom window. I called it poor mans air conditioning and it worked. maybe not as well as genuine a/c but enough that my room was not hot when trying to sleep.

Lot a waisted water too.

I've seen systems that took cool water from deep in a pond run though a heat exchanger then back to the pond.

 

[Brooklyn Tow]

Why on earth would you run with no fan?......You don't think your gonna over heat?

 

[matuva]

JK HD clutch is, IIRC, a modded Hayden severe duty clutch. It does engage sooner, longer than the stock ones.

May be just pull it out and sell it, replace with a stock, or shorten the coil 1/5~1/4 inch to free the clutch and make it engaging later and at higher temps...

 

[DennisG01]

Why on earth would you run with no fan?......You don't think your gonna over heat?

Not sure that I would. See Guy's post... #9. I was mainly curious that if it would increase MPG a respectable amount I would give it a go. Doesn't seem like that's the case.

 

[DennisG01]

JK HD clutch is, IIRC, a modded Hayden severe duty clutch. It does engage sooner, longer than the stock ones.

May be just pull it out and sell it, replace with a stock, or shorten the coil 1/5~1/4 inch to free the clutch and make it engaging later and at higher temps...

In the late Spring to Fall I tow pretty heavy with it and I'm very happy with the performance/temperature handling of JK's clutch - I wouldn't want to alter that. Good thought, though.