I was just wondering about my fan. How do you know if the clutch is bad or if it is on to often. I think that mine is on all the time is that normal or what? Or does it always go on when u start it?

 

If you hear the fan all the time the clutch is kaput.
SPin the fan with the engine off, of course. It should have resistance but it should move. The fan may be on when you first start it but will go off within a minute or so.

 

Cuda, in what weather temps happens this: ....will go off within a minute or so? because I have the sensation that here, the fan is always on, I have to check that.


Thanks

 

Idk, I still think the fan would kick off during a cold start.

 

This is what I found in the repair manual. It' will take some specialized test equipment to do the test. If suspect the clutch is bad you should replace it. If it gets bad enough it can break and go through the radiator. The radiator shop in my area claims he gets quite a few damaged radiators from the fan clutch breaking. Most of them are ambulances or vehicles that set at idle a lot though.

Spin the fan. A light resistance should be felt. If there is no resistance or very high resistance, replace the fan clutch.

<TABLE cellSpacing=0 cellPadding=3 border=1><CAPTION>Fan Clutch Specifications </CAPTION><TBODY><TR><TH vAlign=bottom align=middle rowSpan=2>Engine </TH><TH vAlign=bottom align=middle rowSpan=2>Vehicle </TH><TH vAlign=bottom align=middle rowSpan=2>Equipment </TH><TH vAlign=bottom align=middle rowSpan=2>Water Pump Pulley Ratio </TH><TH vAlign=bottom align=middle rowSpan=2>Engine rpm Required to Run Water Pump at 3000 rpm </TH><TH vAlign=bottom align=middle colSpan=3>Water Pump Fan Test Speed </TH></TR><TR><TH vAlign=bottom align=middle>Minimum Fan rpm at Disengagement Temperature </TH><TH vAlign=bottom align=middle>Minimum Fan rpm at Engaged Temperature </TH><TH vAlign=bottom align=middle>Water Pump Test Speed </TH></TR><TR><TD vAlign=top align=middle>7.5L

(460 CID) V-8
</TD><TD vAlign=top align=middle>F-250, F-350

and F-Super Duty
</TD><TD vAlign=top align=left>with A/C </TD><TD vAlign=top align=middle>1.25 </TD><TD vAlign=top align=middle>2400 </TD><TD vAlign=top align=middle>1900 @ 141°F </TD><TD vAlign=top align=middle>2600 @ 211°F </TD><TD vAlign=top align=middle>3000 </TD></TR><TR><TD vAlign=top align=middle>7.5L

(460 CID) V-8
</TD><TD vAlign=top align=middle>F-250, F-350

and F-Super Duty
</TD><TD vAlign=top align=left>Without A/C </TD><TD vAlign=top align=middle>1.25 </TD><TD vAlign=top align=middle>2400 </TD><TD vAlign=top align=middle>1900 @ 125°F </TD><TD vAlign=top align=middle>2600 @ 195°F </TD><TD vAlign=top align=middle>3000 </TD></TR><TR><TD vAlign=top align=middle>7.3L Diesel </TD><TD vAlign=top align=middle>F-250, F-350

and F-Super Duty
Chassis Cab
</TD><TD vAlign=top align=left>All Options </TD><TD vAlign=top align=middle>1.1 </TD><TD vAlign=top align=middle>3000 </TD><TD vAlign=top align=middle>650 @ 122°F </TD><TD vAlign=top align=middle>2900 @ 200°F </TD><TD vAlign=top align=middle>3300 </TD></TR></TBODY></TABLE>

Disengaged Fan Clutch Requirement Test — Cold

1. WARNING: TO AVOID THE POSSIBILITY OF PERSONAL INJURY OR DAMAGE TO THE VEHICLE, DO NOT OPERATE THE ENGINE UNTIL THE FAN HAS BEEN FIRST EXAMINED FOR POSSIBLE CRACKS AND SEPARATION.
   
   Using a suitable marker, mark the water pump pulley (8509), one of the fan blade retaining bolts and the crankshaft pulley (6312).

1. Connect a tachometer to the engine.

1. Install a throttle adjusting tool.

1. Connect a Sun Strobe Light or equivalent. This can be an SLT-1 or SLT-2 Strobotach or an STA-1 Strobe Trigger adapter for the Sun Distributor Test Stand. A Digital Photoelectric Tachometer 055-00108 or equivalent can also be used for this test.

1. Start the engine and run it at approximately 1500 rpm until engine temperature has normalized.

1. Adjust the engine to the testing speed in the Specifications at the end of this section.

1. Operate the strobe light at water pump test speed and aim it at the water pump pulley. Adjust the engine speed until the light flashes and the water pump pulley marks are synchronized.

1. Aim the timing light at the fan retaining bolts. Adjust the strobe light until it is synchronized with the marked fan retaining bolt (fan appears to stand still).

1. The fan speed must not be greater than the specified fan test speed at water pump test speed.

1. Turn the engine OFF.

1. If the fan speed was greater than the specified fan test speed, check for proper parts usage.
   
   If the correct parts are used, replace the fan clutch.
   
   If the part(s) are not the correct ones, replace the part(s) and perform the test again.

1. If the Engaged Fan Clutch Requirement Test is going to be performed, do not remove the tachometer, strobe light or throttle adjusting tool.

1. If an Engaged Fan Clutch Requirement Test is not going to be performed, remove the tachometer, strobe light and throttle adjusting tool.

Engaged Speed Fan Clutch Requirement Test

1. WARNING: TO AVOID THE POSSIBILITY OF PERSONAL INJURY OR DAMAGE TO THE VEHICLE, DO NOT OPERATE THE ENGINE WITH THE HOOD OPEN UNTIL THE FAN HAS BEEN FIRST EXAMINED FOR POSSIBLE CRACKS AND SEPARATION.
   
   If the Disengaged Fan Clutch Requirement Test was not performed, follow Steps 1 through 5 under Disengaged Speed Fan Clutch Requirement Test.

1. Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille (8200). This will raise the temperature of the air striking the fan clutch and should cause the fan blade to operate at maximum speed.

1. Place the air conditioning selector, if so equipped, in the maximum position and the blower switch in the high position.

1. Adjust the strobe light to water pump test speed.

1. Start the engine and adjust it until the water pump pulley is synchronized with the strobe light. This will be near the engine testing speed given in Specifications.

1. Synchronize the timing light with the fan to fan clutch retaining bolt.

1. The fan speed must meet or exceed the specified minimum fan blade test speed at water pump test speed.

1. If the fan speed was less than the specified fan test speed, replace the fan clutch.

 

IMHO lose the clutch and go electric much more efficant and less wear. You'll love it. I think to myself that its one of the best things I could do for my truck.

 

Cuda, thats a very good write up. thanks. But I think it is difficult to get the specialized test equipment to do the test LOL.

Casey you dont have any issues with electrics in any weather or towing?

 

Electric fans do well on trucks with a stick not so well with a auto trans.

Bill

 

Bill are you just thinking more heat from the trans to get rid of? or is there something I am missing?

 

The heatload from the autotrans is more than the motor.

Also with the electric fan your motor oil temp will raise some.

If you have a defective thermostat (bypassing) under normal driving conditions you dont even need a fan on the PSD (manual box).

Bill

 

Madvan, have you checked the Casey´s Gallery for the set up his fans?, I dont know if he has an auto or stick.

 

i've heard from guys running in the 11s and 12s that they don't do anything.. people actually claim electric fans are worse then the stock fans... danny elmore said he can't tow anything big with them

 

I have tried electric. They just dont cut it with an auto if you work the truck.
2 problem areas i had was towing and crawling around on hot soft beach sand

Bill

 

Uh oh. Beach sand (dunes) and electric fans don't mix???? Thats not good! Bill have you done the fans in your van? just wondering if there is much difference in the rad between the truck and the van that it might work better on a truck than a van. I know I have heard many say towing heavy with electrics doesn't work too well but I don't tow much so thats not a big deal.

 

TJ

E and F are about the same (cooling wise). The E has a higher under hood temp.

Bill