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Engine cooling question

523 Views 4 Replies 4 Participants Last post by  b09676
OK guys, I know this has been discussed many times but I am in a debate about clutched fans, as I am in the process of doing a new radiator / shroud installation. The question pertains to the cooliong benefit achieved with a fan clutch.

My car only has a problem running warm at idle and slow speeds, never at highway speeds.I believe a clutch in my car would be on no benefit for cooling, although I do recognize that there would be a performance increase when the fan freewheels at higher speeds.

Am I correct in saying that the clutch only serves to unload the fan at higher vehicle / engine speeds but provides no advantage at idle?In other words, I think the fan still turns at engine speed , even with a clutch, as long as we're talking idle speeds.

Please respond asap as I have already started to do the work and have not planned to buy a clutch unless you all tell me differently.
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· Registered
1,107 Posts
i think the fan is engaged at idle because that's where you will need the most air pulled thru the rad.
I thought a clutch fan has a thermostatic spring/coupler in the housing that engages the fan blades according to the temperature, so when it's hot regardless of engine speed or vehicle speed the fan would be pulling air.

· Registered
835 Posts
I have found that many people have the four bladed fans when they should be running more for better flow. Even in the books they recomend upgrading fans & rads with a/c systems p/s .

· Super Moderator
8,649 Posts
There are actually two types of fan clutches. One is thermostatic. I believe the other decouples at speed. Neither will make your car run cooler, if that is your question. Both can potentially make your car run warmer.

My cooling system used to run hot on my '65 vert. It hasn't in several years. Here's what I did.

1. Installed 4-row modine radiator in place of 2-row stock unit.
2. Installed aftermarket fan spacer to get fan about 1" from radiator.
3. Installed reproduction shroud and brackets.

I've also replaced the radiator hoses and water pump while I was rebuilding my engine...but that was more out of the principal of "while I'm here I might as well replace this" rather than because of any problem.

I've actually thought about going to a thermostatic fan clutch to see if I could free up some power. I'd hate to run the experiment without a really good temperature gauge in place...and the stock gauge doesn't really quallify.

Good luck with your project.

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