electric cooling fan help...

[Vodka0tter]

My electric fans are rarely on as well. This year has not been bad but even n triple dig I still didn't notice the fans unless I was running in light to light traffic. Also opens up the engine bay a lot. I dont think the butt dyno will ever notice the difference, more a personal choice for many people.

 

[kennythewelder]

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[AK49BWL]

Yeah, in your case the extra load on the engine comes from the alternator instead of the fan clutch.

I see you didn't read the whole post, and that you're set in your ways. That's fine. Experience doesn't lie and I know what mine has been. It tells me you're wrong.

 

[kennythewelder]

Again, click my link.
https://www.gmt400.com/threads/electric-fan-swap-on-the-cheap.41756/#post-1006460

 

[L31MaxExpress]

Why do those with clutch fans seem to think electric fans run all the time,when mine rarely ever come on at all. Hard on alternator? Yeah,if they run all the time. Only a moron would hook them up that way. Had my factory alternator rebuilt one time in 20 years.

Because my electrics ran ALL the time on high speed and could not keep the engine under 240°F despite having a 454/8.1 radiator. I had the PCM controlling them on both engine temp and a/c head pressure. Crawling along in DFW traffic with the a/c blasting the temps would just keep creeping up. If I pulled over and let the engine idle without any load on it they would drop the temps back to about 210. The Duramax fan pulls enough air to keep the engine under 185°F almost year round. Even tugging around the trailer into a parking spot backing up a steep driveway first it stayed under 200°F.

Tahoe dual fans are 40 amps on high when they are in parallel and 10 amps when in series on low speed. Just what they are.

I had a GMT400 pusher fan on with the Tahoe fans as well. Made a noticeable difference in idle a/c temps. After installing the Duramax fan I tested the effect of having it running vs being disabled on a 105°F day. The pusher made ZERO difference with the mechanical fan so I pulled it off and put it on my Tahoe.

 

[L31MaxExpress]

Why do those with clutch fans seem to think electric fans run all the time,when mine rarely ever come on at all. Hard on alternator? Yeah,if they run all the time. Only a moron would hook them up that way. Had my factory alternator rebuilt one time in 20 years.

I have been through 2 CS-144s and have an AD-244 currently that needs the bearings replaced. Conversion vans are heavy on power draw to start with not including the 50 amps of electric fans I ran on it at one point. Tahoe fans drew 40 amps steady and the GMT400 pusher pulls 10 amps steady. Startup spike is double that. I had to play with the idle air compensation for fan 1 and 2 in the PCM to keep the idle from dipping when the Tahoe fans kicked on.

 

[L31MaxExpress]

I see you didn't read the whole post, and that you're set in your ways. That's fine. Experience doesn't lie and I know what mine has been. It tells me you're wrong.

In my experience on numerous vehicles over the past 15 years its generally not worth it to convert to electrics atleast in DFW.

At 190K miles my Infiniti has been through 2 alternators and a set of fans. Because of all the stop and go traffic and idle time it probably has the equivalent of more than 300K highway miles on it though.

 

[89GMCJOHN]

I agree I had a pretty hot Buick Big block build / transplant in a car with a tight engine compartment and limited radiator grille opening ...pretty much a recipe for disaster . In Florida
with the dual electrics it would creep to 205 in stop n go traffic quick .....I then went to a factory 7 blade 18 inch GM metal fan and new suburban fan clutch and a factory type shroud ...that bought me stable idle temps and no more than 180 -185 in stop n go Florida summer heat,,,,, I dont think its all about the screaming cfm those electrics create ...I think the shroud design probably plays more of an important part than people realize and those electrics usually have a thinner shroud..just my experience FWIW

 

[L31MaxExpress]

I agree I had a pretty hot Buick Big block build / transplant in a car with a tight engine compartment and limited radiator grille opening ...pretty much a recipe for disaster . In Florida
with the dual electrics it would creep to 205 in stop n go traffic quick .....I then went to a factory 7 blade 18 inch GM metal fan and new suburban fan clutch and a factory type shroud ...that bought me stable idle temps and no more than 180 -185 in stop n go Florida summer heat,,,,, I dont think its all about the screaming cfm those electrics create ...I think the shroud design probably plays more of an important part than people realize and those electrics usually have a thinner shroud..just my experience FWIW

I don't think it is so much the fan shroud. The electrics just cannot pull the same kind of CFM a locked in clutch fan can. The best dual electric setup may pull 5-6,000 cfm. The clutch fan can pull 10-15,000 cfm when the rpm comes up. In my scenario that Duramax fan has a very aggressive pitch and the blades are massive. Its meant to cool a turbo diesel pulling a 15,000 lbs trailer, it moves some crazy CFM. In the rare event the fan clutch actually engages it pulls about 10 ft/lbs compared to it freewheeling and sounds like a medium duty truck or semi truck. It will chirp the belt when it engages and then ROOOAAARRR. The temp gauges plumets and within seconds it goes back to near silent freewheeling.

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[89GMCJOHN]

Good info ...just for posteritys sake - what yr ,model , fan , fan clutch combo are you recommending for max cooling that a guy could pull out of a junkyard .