Series 2 dual cooling fan swap to larger single fan

Hi all

As some of you have seen I’ve been trying to stop my car from running hot. Through the group, and a couple of individuals in particular, I’ve identified what I think is the culprit, a bad thermostat.

But while I’ve been working on this, I came across an older, high capacity, 16” fan that’s been lingering in my garage. Not sure of the brand. Low profile, maybe 3” deep. It has me wondering about fitting it to the e-type.

The amount of area covered by the fan would be dramatically larger than the two 10” fans. The swept area of the actual fan blades seems vastly larger. (Total number of inches of fan blade is what I’m thinking)
Summit racing has customizable aluminum fan shrouds of various sizes.
Any thoughts?

Be certain the rotation is correct

Besides the size of the fan you should be concerned about the CFM rating and amp draw. The CFM and amp draw will change as the static pressure at the fan changes. Static pressure, very loosly defined, is a measure of the resistance created by things like a radiator placed in front of the fan. The higher the static pressure (or to put it another way, the more there is something in front of the fan to impede airflow the lower the CFM and usually the higher the amp draw. The below link explains static pressure.

For example, open the below link and compare the specs of the cheapest and most expensive fan. There is a lot of difference.

That 16 inch fan you have in your garage may be great or it may be not so great. Only a review of the specs will tell for sure.

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Does that 16" fan have a brand name on it? Here’s Mike’s chart comparing both CFM & amps for the various 16’s:

And here is a comparison of the 10" fans on the market:

Obviously you have to double the 10" numbers to get the complete picture there.

For me the choice was simple - I went with his 10" fans - quite adequate even in city traffic in a Tucson summer:

Hi John
From what I can tell it’s 2100cfm at 9 amps

But what do you think of the idea?? That is, a bigger single low profile fan and shroud?

I’m not trying to be negative but what is it’s CFM when you throw a radiator in front of it. When I had the 2+2 I bought a sheet of aluminum and what I thought was a decent 16" fan. I fabricated a shroud and installed the fan. I had no data to back it up but my impression from the temp gauge was at best I’d equaled the factory setup.

For grins I built a 3" long wind tunnel with a 12"X12" cross section to compare 10" cooling fans. I placed thin wires at the outlet end of the tunnel to give me 9 reference points to measure air speed with an anemometer . The airspeed will vary at each point but I figured I had enough points that I could average them and get something meaningful. I compared the square motor with the stock blade to the round motor with the stock blade to the round motor with an aftermarket blade.

The square motor moved the least amount of air, the round motor with the aftermarket blade moved the most air and the round motor with the stock blade fell in the middle. All were 10" fans that fit in the stock shroud with the divider installed between the two halves.

I’m running the round motors with aftermarket blades. The engine was rebuilt 5,000 miles ago, the cooling system is clean and stock, antifreeze is a 50/50 mix. I poured in a bottle of Water W#etter, figuring it couldn’t hurt, but in reality I probably just wasted the money. With the AC on, sitting in traffic in 98 degree heat, the coolant temp never has gone above the “L”.

Thanks again for your thoughts. Interesting that your 2+2 had the 16 “ fan set up. As Michael suggested on an earlier post, I’m probably overthinking this… the new thermostat housing is here, and a new thermostat and gaskets are on the way.

I have the dual round motors with the aftermarket blades and they seem to move a lot of air, so maybe it’s just a coolant flow problem

Hopefully this will get my temp down so that I don’t feel I’m running on the edge all the time.

If that doesn’t get me where I need to go, I’ll pull the radiator, as i think I’ve exhausted all other possibilities.

The S2 radiator/fan setup works VERY well, when everything is in good condition. Changing fans is completely unnecessary. Figure out what is wrong with your system, and FIX it.

Ray L.


:+1: 20 characters…

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As a pedantic point, it’s best to “cover” the radiator in air flow. As a practical point, the S2 radiator is down flow, so having two fans located near the top concentrates air where it’s most needed.

I think I already mentioned one good, simple mod: bend a strip of sheet metal and rivet it to the shroud so that the two fans are separated.

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I was about to mention this too. If the sII system is in good condition, I have sat in hot weather, bumper-to-bumper stop and go on a freeway in Phoenix and it just ran a bit over “normal”.

And that was with the A/C turned on.

So the first thing is to get it properly set up. Common difficult problems to diagnose are an impellor that the blades have deteriorated and it doesn’t pump water, or that the block needs boiling because all the sand was not originally washed out of the block.


Wherever space and time interact, there is information, and wherever information can be ordered into knowledge, and knowledge can be applied, there is intelligence.
Pavel Mirsky, mid 21st Century Russian General

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Through 46 years of ownership of my '68 and 200k plus miles, some through more than 100 degree driving the two fan system has always worked - more than worked - there hasn’t been a time when it was even marginal. The original square motors failed back in the 70’s, but the round replacements are still in the car. One of them had a brush failure 5 years ago but new brushes added and it’s working fine now. That led to installing the metal strip between the halfs like Mike suggests, but so far had no chance to use it. Living most of that time on the Canadian prairies means that the car has always had at least a 50/50 blend of anti freeze for storage and summer, so the rad has never been apart or cleaned in a rad shop.

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„I‘ll pull the radiator, as i think I’ve exhausted all other possibilities.“

I have the stock setup, with a/c. I had the radiator taken apart and new mesh fitted. The square fan motors are original. Two seasons of driving in up to and around 90 degree weather in traffic never once overheated or ever got to the L. To be fair I didn’t use the a/c. Fans are not your problem.

I had my original radiator boiled (much cheaper, and sufficient). It had a couple pin hole leaks, but has been fine for over twenty years now.


Wherever space and time interact, there is information, and wherever information can be ordered into knowledge, and knowledge can be applied, there is intelligence.
Pavel Mirsky, mid 21st Century Russian General

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