Repairing Problems With Your Imperial's Fan Clutch

Imperial Home Page -> Repair -> Cooling System -> Radiators -> Fan Clutch

Question from John:

I'd say my fan clutch is about 3/8" from the radiator. I can't fit my finger in there. What if you got a short fan and used shims to give you the right distance? It needs to be close, otherwise, the thermal action of the clutch won't work correctly.


From John:

I replaced the fan clutch on my car (identical to yours) awhile back. I can no longer read the brand name on what's left of the (orange) box, but the part number is TFC-49. This is a thermal fan. A previous owner had put a solid "clutch" on so the fan turned at full speed at all times, making a lot of noise.

It also says this fan replaces:

Everco A8197/8
Kool Klutch 115049
Hayden 2705
Murray 271305

From Nancy:

Exactly what Imperial do you need a fan clutch for?  You can try Neils Auto Parts  in Riverdale, MD.  We usually have no trouble finding clutch fans for Imperials in the DC area.

Follow-up question from Paul:

I just couldn't stand it any longer not being able to drive my Imperial for lack of a fan clutch... I broke down and ordered a flex fan and installed it on Saturday. I'm back on the road again.

The flex fan I got is one of the heavy duty, stainless steel types, with blades that look sort of "normal". I just need some good road dirt and oxidation on it so it looks "right". Some of the more common flex fans are made of nylon or aluminum, in kind of a toy "pinwheel" shape, some with red or blue anodizing... I didn't want one of those.

I still want to get the thermostatic fan clutch back in when I can locate the right one. I'm kind of attached to the original fan, it's got one of those "DPCD" logos on it.

The real issue is probably not finding the fan clutch, it's finding the right part number and then perhaps ordering it if it's not in stock. I'm sure it's still made, it might even be the alternate that's listed for a 1965 Chrysler, the places I've dealt with so far just don't have a listing for a 1965 Imperial, and haven't had the alternate in stock. Both the Imperial and Chrysler use the same part in the 1965 parts book. But that doesn't mean what fits in the Chrysler will fit in the Imperial, as I found out. Anyway, my car is a normal 1965 Imperial, 413 with A/C.

Update from Paul:

I'll give you update on my 1965 Imperial that had the water pump failure on Saturday. Well, there was no problem getting a new water pump and installing it, but the fan clutch, now that's another story. I haven't been able to locate one that will fit so far, the closest tip I've gotten so far was from someone with a 1964 New Yorker.

My car is the 413 with the standard A/C setup: seven blade fan with thermal clutch (Leece-Neville, I believe). The fan clutch is very short since the radiator is mounted very close to the engine with an almost non-existant fan shroud. That's the problem, I can't find a replacement clutch that's short enough.

Anyway, here's a little picture of giving the dimensions of the fan clutch THAT DOESN'T WORK, and where the problem is.

(water pump)

+------+<---------------------- water pump hub mating surface
+-+ +-+ | |
| | A |
| | | |
+----+ +----+<------------- C -- fan attachment surface
| | | |
+-----+ +-----+ B |
| | | |
+------------------------+<------------- front surface of clutch


The water pump to fan dimension (A) is 1-3/8 inches (about right). The fan to front of clutch dimension (B) is 1-7/8 inches (too long). The overall length (C = A+B) is 3-1/4 inches (also too long).

This one is an aftermarket generic "Imperial" Thermo-Trol, I also looked at one for an M-body from NAPA which turned out to be identical, just in a box with a different name. I asked if they had any other units that might be shorter, and was shown a velocity (rather than thermal) clutch, it was shorter in dimension B above, but longer in dimension A, giving the same overall length.

I'll have to take the old clutch back off to measure it. I reinstalled it when I discovered my replacement wouldn't fit, and didn't realize how far gone it was until I after I started the car back up.

Question from Chris (1972):

Other than noise reduction, is there any practical advantage to having a clutch-type radiator/cooling fan on my 72 LeBaron? Is there a way to test the clutch off the car? I took my car out today on a leisurely 45 minute drive through the country, cruising along at a max of 45-50 mph, I noticed the temp gauge was indicating a temperature higher than normal, and when I would stop for at an intersection/crossroad the gauge would climb higher and higher, when I got home I shut the car off and lifted the hood, after a quick look for leaks, I grabbed the fan and turned it,-it offered little or no resistance, even though the underhood temperature was noticeably higher than normal, so I let it cool down while I went looking through the archives for a replacement clutch, I found in my stash a clutch marked 440,used- (not in my handwriting-this is the reason why I want to know if there is a way to test a clutch -off car) and I also found a clutchless fan with spacer, which I then installed on the Imp---temperature seems to be back to normal after a ten-minute test drive, this "new" fan is noisier, but if that's the only drawback, I'll probably just leave it on the to summarize :

Is there any advantage to the clutch fan?

Is there a disadvantage with the clutchless fan?

Is there a way to test a used fan clutch off the car??


From Steve:

>Is there any advantage to the clutch fan? 

Yes. Increased gas mileage, decreased noise, decreased stress on the water pump.

>Is there a disadvantage with the clutchless fan. 

Decreased gas mileage. More Noise. Increased stress on the water pump. Can cause overheating if used with fan shroud.

>Is there a way to test a used fan clutch off the car?? 

Its one of those things you just have to try by feel. There should be some resistance in the fan clutch, especially when it is cold like first thing in the morning. Best bet is to replace it with a new one as they are still readily available and not that expensive (about $20).

Clutch fans are generally used on A/C cars and with fan shrouds. You don't want to use a clutchless fan with a shroud as the clutchless fan actually starts to block air above 40 or 50 mph and can cause overheating problems on highway runs.

From David:

I'm not sure how to test it but other than reducing noise it allows better gas mileage. Above 50mph or so the fan is not really needed. In the middle of the fan facing the radiator is a coil, this coil is a "thermostat" of sorts. When the air passes through the radiator and heats up it causes the coil to engage the clutch which activates the fan. When the air cools enough at speed it cools the coil deactivating the clutch and the fan free wheels reducing drag on the engine increasing gas mileage and power.

From Leo:

Flex fans are known to "eat" radiators, I'd stay away from them.

From Bob:

The center section of the fan (which is finned, like a heat sink), I believe, contains a viscous fluid which, when cold is very thin and permits free wheeling. When the temperature heats up, the fluid becomes thicker and is stiff which makes a more or less "solid" connection between the core and the blade.

From Wayne:

I had a clutchless fan on my '72 LeBaron, which failed at high speed and destroyed the radiator and fan shroud. It was a "flex" type fan which someone had added. Since I have had a clutch type fan, I have not had any over heating problems. The car is a little bit louder, since the mechanism is heavier.

Question from Dan (1983):

I have removed the 4 bolts from the front of the water pump pulley, and the 4 bolts from the viscous drive unit that the fan is attached to.

So, how does the fan come off? Does it slide off the pump shaft? Can I pry on the flange w/o breaking anything?

Can I pry on the viscous drive, between it and the fan itself?


From Dave:

Take a piece of cardboard and put it between the fan and radiator and then gently tap the fan from behind with a piece of wood and hammer. The four bolts that hold the fan to the pump are all that hold it in place and it may be rusted in place. There is a small tip on the end of the water pump that is used to center the fan to the pump when it's installed, makes it easier that way.

From Dick:

There is nothing else holding the fan on but pure contrariness and a buildup of crud. Gently wiggle the fan blades back and forth while gently prying between the fan center sprocket and the thingy it is stuck to. Don't beat or pry on the viscous fan coupler itself, it can't take it! And by the way, when you get it off, be sure to store it in the same upright position it is when installed on the car - otherwise the viscous fluid will move inside the unit and you'll have no automatic fan operation until it re-initializes itself, which takes a few hours of running.

From Neil:

I know Dick B has mentioned laying out the viscous hub whilst you are pulling the engine out, there is a picture and explanation in the FSM to clarify which way up it should be.

This page last updated May 19, 2004.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club