[laynrubber]

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.

 

[mrchips]

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 .

 

[HoosierBuddy]

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.

Phil

 

[b09676]

Thanks folks, exactly the info I was looking for. I will proceed with a new high efficiency 3 row core using my existing original style tanks and a new shroud. I already have a 5 blaeded fan in there.