Radiator Fans Wars: Electric vs. Mechanical or Both!

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

no...question...when under load and in the rpms....fan clutch type setup is the $hit... electric fans excel at cooling in the low engine rpms....@ idle etc.. because the fans normally run at 100% when on an so regardless of engine rpm the fans are moving air at 100%. I think the trick to the whole business is to have a great shroud setup, a good radiator and a fan clutch & fan that will move decent amounts of air at idle and low rpms....to include when the clutch is fully engaged at mid-range rpms.

that's one thing I noticed on the OEM yota fan clutch and fan....that it moved a good bit of air at idle and low rpms. When I had the I-6 I've let it run a long time with A/C on at idle in middle of summer to see what it would do....never onverheated and you could feel the air moving across the radiator from the grill area externally. Old school but very good.

I've seen some articles where people talk about modifing the GM fan clutch but I've never personally tried that. Good to have a high idle capability with A/C on for cooling purposes too.
 
Elbert said:
Good to have a high idle capability with A/C on for cooling purposes too.
Click to expand...

Not a bad idea!

Commercial diesel vehicles have a high idle switch that can be set when parked. I'm sure that would not be hard to do.
 
1967 TLC said:
.

Thanks on all the shroud comments!!

The new radiator shroud preformed great!

I took the wagon out in temps between 100 and 108 degrees. Freeways, moderate grades and a 6 degree grade in 4th and 5th gear over Cajon Pass into the high desert.

At freeway speeds, the coolant temps stayed at 180 degrees; at a slight grade, with 108 outside temps the coolant went up to 190 degrees.

In stop and go traffic in 104 to 105 degree temps the gage hovered around 200 degrees, but quickly dropped back down once I started shifting through the gears.

A/C on the whole time.
Road speeds between 70 and 75 mph.
180 thermostat.
Elbert: The original fan was an offset five blade. I bought a steel 6 blade designed for a big block.


I’m very pleased with my test run. Other than in the stop and go traffic, the radiator temps did much better than with the electric fans, but just jumping up the rpms would drop the temps when stopped.

I think I have solved my high heat issues. The next big test will be fully loaded with the roof tent.



.
Click to expand...

Hey 67,

Got a p/n on that 6 blade fan?

Having problems keeping my 350 TBI cool in my 60.

Don
 
'Hey 67,

Got a p/n on that 6 blade fan?

Having problems keeping my 350 TBI cool in my 60.'


Don

Unfortunately, I don't have the part number. I brought my 5 blade fan clutch to my local parts shop and matched it to a big block chevy fan clutch assembly. The part number is long gone.

The fan blade is only part of the equation. The radiator, thermostat and fan clutch all need to be in good working order and I think, most important is a proper fitting fan shroud.

In my case the fan shroud was the last piece in the engine cooling puzzle. And if I had moved fan shroud from last to first on the list, it would have saved me about $450 in unnecessary radiator work.
 
go to the flex-a-lite web site... they have the old school steel 6 blade fans for a fan clutch setup (GM).
 
Elbert said:
snip....

I've seen some articles where people talk about modifing the GM fan clutch but I've never personally tried that. Good to have a high idle capability with A/C on for cooling purposes too.
Click to expand...
I'd be interested in any links that you might have on the GM fan clutch mods.

1967 TLC said:
Not a bad idea!

Commercial diesel vehicles have a high idle switch that can be set when parked. I'm sure that would not be hard to do.
Click to expand...
Smaller engines, like the 4A-GE in my MR2, go to an idle-up mode when the A/C is turned on. A friend with one of these engines in a Sami "false-feeds" that ECU sense wire to get a high idle when crawling through the rocks.
 
MAF has an Australian 8-blade plastic fan; I'm guessing it moves more air than the US one?
Most of you guys with cooling issues seem to be running V8's; how to the contour fans work with the 2F? Planning to do that mod at some point as long as ya'll don't scare me away.
 
ntsqd said:
I'd be interested in any links that you might have on the GM fan clutch mods.

I'll look, I had a link I had saved on my newsgroups reader (but since I don't screw with the newsgroups anymore that got deleted. The mod related to taking the clutch apart...and making some minor adjustments to the bi-metalic strip or metal "tang" in the fan clutch hub. I'll post a link if I come across it...some guy had it on his web site. Basically made the clutch engage sooner.

I think the GM OEM fan clutchs work well, never had much trouble with them.

I'm debating going with a fan clutch setup on my 60.... something like the OEM setup of a 1999 GM truck with 5.7. and getting my friend to build me a shroud out of light guage sheet metal. Once I get the A/c going I guess that will be the deciding factor.
Click to expand...
 
tclark said:
Most of you guys with cooling issues seem to be running V8's; how to the contour fans work with the 2F? Planning to do that mod at some point as long as ya'll don't scare me away.
Click to expand...


I used a Contour electric fan setup for two years on my 350 v8 conversion. On the trail and on the flat lands it worked great. Stop and go traffic was great. The only time I noticed it did not cool as well as I would like, was when I left the comforts of the coast and headed fully loaded into the hot desert. At high freeway speeds, with the engine under constant strain ,the electric fans just could not cope. Of course, I was building an overland truck and the fact it would not cool properly on the open road, lead to my cooling solution found in this thread.
 
Anyone have the part number or good place to buy the 6 blade fan or High pressure cap that fits a stock radiator? I'm pretty happy with my v8 setup but I bent the fan when I built my shroud and the cap is really old so I was going through anything I didn't replace when I did the swap 2 years ago and I figure I might as well replace with better.
 
Kurtis said:
Anyone have the part number or good place to buy the 6 blade fan or High pressure cap that fits a stock radiator? I'm pretty happy with my v8 setup but I bent the fan when I built my shroud and the cap is really old so I was going through anything I didn't replace when I did the swap 2 years ago and I figure I might as well replace with better.
Click to expand...


I don't have a part number, but I brought in my 350 fan to a good quality auto parts store and matched it up to a Chevy 454 motor 6 blade fan. Fit perfect. Sucks major air! I used a 13 pound pressure cap. Works great.

.
 
Last edited:
noticed this thread is alive again. Update to this I dropped the electric fans and with the OEM GM fan clutch and fan that fit my 1999 5.7 Vortec. Same fan and fan clutch fit the 97-99 pickup/suv with 5.7, you might even be able to run the fan off of the 5.3 setup too... single belt setup. these are the fan clutches with the large single nut as opposed to the older model 4 bolt setups.

You can find a number of 6 blade radiator fans deisgned for fan clutch use on the flexalite web page...as I noted before I ran one of these fans on my 92K1500 I had without issue with 5.7 TBI.

Mechanical radiator fan clutch and matching radiator fan is the way to go, hands down the best cooling solution. My truck is no light weight and this has worked the best for me.
DSC00482.webp
DSC00484.webp
DSC00485.webp
 
Looks like you can according to dallen341. I think I have a older fan clutch around here somewhere...one of the 4 bolt types.... I know there is some difference between the old school v belt fan clutch which is 4 bolt and the 4bolt type clutch that is used in the TBI trucks maybe some thing along the lines of the diameter of the large center hole is different (where the fan sites down on the clutch).

Anyway if I find that other clutch I'll post up a pic with it and the fan (I have a spare fan).

I think the fan like the above and the one used for the 5.4 and 6.0 truck engines seems to work very well.
 
Nice to see the thread again...

I have since gone to a stock GM mechanical fan and fan clutch for my 5.3 V8 and have to say hands down it is the way to go. A good shroud is key with the setup though, you have to make sure the shroud directs the air from every part of the rad through the fan. don't make the shroud too close to the rad either.
 
Elbert said:
noticed this thread is alive again. Update to this I dropped the electric fans and with the OEM GM fan clutch and fan that fit my 1999 5.7 Vortec. Same fan and fan clutch fit the 97-99 pickup/suv with 5.7, you might even be able to run the fan off of the 5.3 setup too... single belt setup. these are the fan clutches with the large single nut as opposed to the older model 4 bolt setups.

You can find a number of 6 blade radiator fans deisgned for fan clutch use on the flexalite web page...as I noted before I ran one of these fans on my 92K1500 I had without issue with 5.7 TBI.

Mechanical radiator fan clutch and matching radiator fan is the way to go, hands down the best cooling solution. My truck is no light weight and this has worked the best for me.
Click to expand...

What is the part number printed on the fan clutch you are holding? Pretty sure I work for the company that makes these.
 
Lizardking said:
What is the part number printed on the fan clutch you are holding? Pretty sure I work for the company that makes these.
Click to expand...

the fan clutch is on the truck...if I can see the pn on it installed I'll post the number over the weekend. Its the OEM GM Fan clutch. I bought it from Rock Auto, 1999 GMC Yukon with 5.7 is my donor vehicle. As I recall there is only one GM fan clutch for that engine.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom