Clutch fan diagnosis

While trouble shooting an AC issue, found that the top plastic tank of the radiator is cracked and the fan is very hard to turn. Plus there was a very high force of air coming from the fan. I don't know if the 6.0 fan will cause the extra volume of air.

Until recently, I haven't heard the clutch fan ever lock even towing 21k in 90° weather with hills. The truck always ran cool. Plus my fuel mileage is down.

When I first accelerate from a stop, I hear the roar but as soon as the RPM's drop/shift gears, the roar goes away.

When I shut the motor off, the fan stops spinning instantly.

I've read the Ford diagnostic procedure and I do not have an optical rpm reader.

If the fan has a lot of resistance, loss of mileage and the fan stops instantly when the motor shuts off, could the clutch fan be bad?

Billy T.
[email protected]

I would say its bad.

Snag your wife's kitchen broom. Something with stiff bristles about 6-10" long.
Start the truck and allow the fan to spin up. Shove the bristled end of the broom (I'm sure there are those dense enough to try the handle) into the fan.
-If the fan does not decelerate noticeably when the engine is cool, failed clutch.
-If the fan decelerates, but accelerates lazily once broom is removed, failed clutch.
-If the fan decelerates considerably once engine is at operating temp, failed clutch.

backwoodsboy said:

Snag your wife's kitchen broom. Something with stiff bristles about 6-10" long.
Start the truck and allow the fan to spin up. Shove the bristled end of the broom (I'm sure there are those dense enough to try the handle) into the fan.
-If the fan does not decelerate noticeably when the engine is cool, failed clutch.
-If the fan decelerates, but accelerates lazily once broom is removed, failed clutch.
-If the fan decelerates considerably once engine is at operating temp, failed clutch.

Click to expand...

My fan clutch failed the first test, it didn't stop when the broom bristles were shoved in. Time to start searching for a Horton.

Rusty

Yea fan clutch was locked on all the time. I replaced with a Hayden unit. Since then I found a Horton unit on Ebay. Need to pick up a temp switch.

I'm running a 192° T-stat, I'm going to go with either a 210° or 215° temp switch.

While you're at, consider swapping over to SD dual tensioner.

If you're running a 6.0 fan, you can't run it with the Horton. Need to swap the OBS fan back on. For more info, see the last few pages of the Mishimoto rad thread in the OBS section

Billy T.
[email protected]

I just received my Horton fan clutch kit 996124. It comes with the harness and a NO 210* temp switch, but it's 1/2" NPT. Now to find some time to get it installed.

Rusty