Fan danger?

Had my ragtop out on a beautiful day when a gentleman stopped by to admire. As we talked he told me about his 1972 Cougar with a 351C. He said he was working on it when the cooling fan bust apart. One of the blades almost sheared his right arm off. I’ve never heard of this but he has the scars to prove it. All gearheads know to avoid a spinning fan but this is one danger I hadn’t heard of before. I guess the plastic fan shroud offered no protection. Just passing this along so we can all stay safe.

Ford had a recall of factory flex fans in the mid 1970’s. I believe the DOTA marked fans were the ones affected. The flex fans, even the ones not included in the recall, can crack and shed blades unexpectedly.

D2SE-AA fans were recalled. But there may have been others. This states the noted fans were used on 302 and 351, with A/C and all 351M 400 and 460s. This service bulletin is for 1976 and 77’s, but being the D2SE-AA fan is a 72 engineering number I’m sure it was used on Ford products starting with the 1972 models.

This news story covers 1973 to 77 models.

A buddy of mine had car with the oddest vibration that no-one could diagnose. Finally a mechanic had us take a close look and count the fan blades. Sure enough one had fallen off and wasn’t noticed when it happened. Lesson learned. Thankfully no one was ever in danger.

Chuck here on our forum had 1 explode and part of the shrapnel missed his eye by like inches. I have mine put away and I went with a clutch fan. Way to scary to think that just 1 over rev could actually send a blade thru the bood .


After market fans are pretty affordable & many are made with high performance engines that spin up fast in mind.

Safety and simplicity first.

The clutch is supposed to preserve horse power plus mileage & even though mine has one, in my opinion they are unnecessary.

I’m pretty skeptical that a fan smaller then a typical ceiling fan can affect engines that can easily have over 200 horsepower and tons of torque & that’s just the 2 bbl carb!!

They don’t even really help the vehicle warm up faster. When the engine is cold (unless fuel injected maybe) the cold idle is much higher rpms then normal and the clutch will engage fully.

Mine doesn’t free wheel at all when I start it up.

A fan simply bolted on is more mechanically simple and costs less money. I’m pretty sure it’s more reliable as well.

If overheating is an issue, why not flush out your radiator and use a lower temperature thermostat such as a 180 degree one or even the 160 degree one instead?

Real helpful and knowledgable responses here. I will change out to Summitt Racing item or electric fan if I have one of the recall items. Mine is riveted to a metal hub and only the outer parts of the blades flex. A couple of [poor] photos attached. Can anyone tell from this?

I think you’ll have to pull the radiator to get a proper look at it.

Yes I know most cars on the road have electric fans, electric fuel pumps etc, but I’d go for a mechanical bolt on. It’ll be much simpler & look closer to period correct.

There are a few misconceptions here that are important from a safety stand point.

The fan clutch that came on Cougars is called a thermal clutch. It doesn’t really hook up until the radiator is very warm. If you have a fan clutch that doesn’t freewheel when cold it is either the budget replacement friction type clutch, or it is defective. The distance from the face of the thermal clutch to the radiator is very important. Too far away and it won’t feel the heat and hook up. The thermal clutch actually helps the engine warm up faster than a fixed fan.

The second function of a fan clutch is to limit the maximum speed of the fan. This is why it called a “power saver” fan. At higher speeds going down the highway, the fan really does nothing. The ram air effect of pushing the radiator through the air at several thousand feet per minute moves more air than the fan ever could. So the fan clutch is designed to slip at high RPM.

Never use a clutch type fan blade with out the clutch. The clutch style fan is designed to be more aggressive at low RPMs with larger blades and more pitch. Those larger heavier blades are not designed to spin at 6 or 7 thousand RPM. They can fail in several ways, none that are good.

Ford used fixed flex fans on the Super Cobra Jets because they are lighter ( cheaper too!). The idea was that the flex would allow the fan to be fairly aggressive at lower RPM and then flatten out at high RPM. They worked reasonable well until they developed stress cracks and started throwing blades. Ford began a silent recall, if your car came in for service and it had a flex fan they replaced it with the older design clutch style fan and clutch and a sticker that read Caution Fan. The kit supplied by Ford was very cheap to encourage the updates and for years you could find them as NOS items at great prices. Of course that was back in the late 80’s and early 90s.

Changing a thermostat doesn’t help with over heating. If the AC on your house won’t keep the temp at 75 turning it down to 72 won’t help. If the engine is running above the temp of the thermostat the thermostat will be fully open. A colder thermostat would be just as open, only getting that way sooner. Flushing out the radiator is a step in the right direction.

From what I understand, there are many fans that can be bolted on and can spin up to 6,000 rpms or more without a clutch. Read the fine print.

Yes, they did come with these fan clutches OEM, but in my opinion the typical engine can work just fine without those.

Unless you like complexity for it’s own sake or are preserving an original OEM look, in my opinion, get a direct bolt on fan that is rated for your engine rpms and be happy.

You can set up your choke to work with how fast your engine warms up.

The other issue with clutches is that the fan is further forward and might prevent you from installing a bigger beefier radiator.

Yes, high speed can make a fan redundant, but try driving at very high temps or at higher altitudes, such as going up the mountains on a steep incline.

Under such situations, the engine will heat up more then you expect, not necessarily overheating but still dramatic. A fan can help.

Also, should you find yourself driving below freezing with ice on your grill, airflow can be reduced by a lot.

(I would try to avoid that especially without a locking rear end)

The best way, in my opinion, to just be ready is to have the fan solidly bolted on together with a radiator that’s big enough.

That’s just a fix it and forget it situation.