bad fan clutch??
#1
06-06-2010, 09:41 AM
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#2
06-06-2010, 10:42 AM
#3
06-06-2010, 10:44 AM
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Sounds like it. Toss a blanket in front of the grille at idle and watch the temp, when the fan locks up you WILL know it unless you are deaf, it sounds like a freakin airplane. I'd say if the engine will hit 220 or so without the fan locking up the clutch needs replaced. There is a specific air temp they are supposed to lockup at, I think its around 205-215.
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06-06-2010, 11:54 AM
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Below is a summary from the Ford Service Manual for testing the fan clutch ...and as you can see when the engine compartment temperature reaches 205*F the fan clutch fully engages and provides a maximum fan speed
Fan Clutch Test ...Maximum Speed Requirement...
1) Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille. This will raise the temperature of the air striking the fan clutch and should cause the fan blade to operate at maximum speed.
2) Start the engine and run it at approximately 1,500 rpm until the normal operating temperature has been achieved.
3) Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
4) Adjust the strobe to 3,600 rpm for 7.3L diesel engines and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
5) NOTE: The temperature of the air hitting the fan clutch should be above 96°C (205°F) for maximum fan speed.
6) If the fan blade speed is less than 2,850 rpm on 7.3L engines, install a new fan clutch.
Here's the complete version...
Fan Clutch Test ...Maximum Speed Requirement...
1) Block off areas on each side of the radiator in the engine compartment and the front of the radiator grille. This will raise the temperature of the air striking the fan clutch and should cause the fan blade to operate at maximum speed.
2) Start the engine and run it at approximately 1,500 rpm until the normal operating temperature has been achieved.
3) Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
4) Adjust the strobe to 3,600 rpm for 7.3L diesel engines and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
5) NOTE: The temperature of the air hitting the fan clutch should be above 96°C (205°F) for maximum fan speed.
6) If the fan blade speed is less than 2,850 rpm on 7.3L engines, install a new fan clutch.
Here's the complete version...
...This help? found this out of my Service Manual ...Fan Clutch Test
Spin the fan blade (8600) by hand. A light resistance should be felt. If there is no resistance or very high resistance, the minimum and maximum fan speeds must be checked as follows:
Fan Clutch Test—Minimum Speed Requirement
Use a suitable marker to mark the water pump pulley (8509), one of the fan blade retaining bolts and the crankshaft pulley (6312).
Connect a tachometer to the engine.
Install a throttle adjusting tool.
Connect the Digital Photoelectric Tachometer.
WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been first examined for possible cracks and separation.
Start the engine and run it at approximately 1,500 rpm until the normal operating temperature has been achieved.
Operate the strobe light at 4,320 rpm for 5.4L and 6.8L engines and 3600 rpm for 7.3L diesel engines, and aim it at the water pump pulley. Adjust the engine speed until the light flash and the water pump pulley mark are synchronized.
Aim the strobe light at the fan blade bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade bolt (the fan blade appears to stand still).
The fan blade speed must not be greater than 1,900 rpm on 5.4L engines and 2,000 rpm on 6.8L and 7.3L engines.
Turn the engine off.
If the fan blade speed was greater than 1,900 rpm (on 5.4L) (on diesel engines and 6.8L, 2,000 rpm), install a new fan clutch (8A616).
Fan Clutch Test—Maximum Speed Requirement
Perform Steps 1 through 5 of the Fan Clutch Test—Minimum Speed Requirement.
NOTE: The temperature of the air hitting the fan clutch should be above 96°C (205°F) for maximum fan speed.
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.
Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
Adjust the strobe to 4,320 rpm for 5.4L and 6.8L engines and 3,600 rpm for 7.3L diesel engines.
WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been first examined for possible cracks and separation.
Start the engine and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade bolt (the fan blade appears to stand still).
If the fan blade speed is less than 3,600 rpm on 5.4L engines and 3,500 rpm on 6.8L engines, 2,850 rpm on 7.3L engines, install a new fan clutch.
Spin the fan blade (8600) by hand. A light resistance should be felt. If there is no resistance or very high resistance, the minimum and maximum fan speeds must be checked as follows:
Fan Clutch Test—Minimum Speed Requirement
Use a suitable marker to mark the water pump pulley (8509), one of the fan blade retaining bolts and the crankshaft pulley (6312).
Connect a tachometer to the engine.
Install a throttle adjusting tool.
Connect the Digital Photoelectric Tachometer.
WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been first examined for possible cracks and separation.
Start the engine and run it at approximately 1,500 rpm until the normal operating temperature has been achieved.
Operate the strobe light at 4,320 rpm for 5.4L and 6.8L engines and 3600 rpm for 7.3L diesel engines, and aim it at the water pump pulley. Adjust the engine speed until the light flash and the water pump pulley mark are synchronized.
Aim the strobe light at the fan blade bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade bolt (the fan blade appears to stand still).
The fan blade speed must not be greater than 1,900 rpm on 5.4L engines and 2,000 rpm on 6.8L and 7.3L engines.
Turn the engine off.
If the fan blade speed was greater than 1,900 rpm (on 5.4L) (on diesel engines and 6.8L, 2,000 rpm), install a new fan clutch (8A616).
Fan Clutch Test—Maximum Speed Requirement
Perform Steps 1 through 5 of the Fan Clutch Test—Minimum Speed Requirement.
NOTE: The temperature of the air hitting the fan clutch should be above 96°C (205°F) for maximum fan speed.
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.
Place the climate control function selector switch in the MAX A/C position and the blower motor switch in the HI position.
Adjust the strobe to 4,320 rpm for 5.4L and 6.8L engines and 3,600 rpm for 7.3L diesel engines.
WARNING: To avoid the possibility of personal injury or damage to the vehicle, do not operate the engine until the fan blade has been first examined for possible cracks and separation.
Start the engine and adjust the engine speed until the strobe light flash and the water pump pulley mark are synchronized.
Aim the strobe light at the fan blade retaining bolts. Adjust the strobe light until the light flash is synchronized with the marked fan blade bolt (the fan blade appears to stand still).
If the fan blade speed is less than 3,600 rpm on 5.4L engines and 3,500 rpm on 6.8L engines, 2,850 rpm on 7.3L engines, install a new fan clutch.
#5
06-06-2010, 01:37 PM
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#6
06-06-2010, 02:29 PM
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No, just let the truck get up to 220 or so and you should hear the fan lockup, it will be VERY loud and it will move ALOT of air. You may want to verify temp with a infrared gun if you have one, just to make sure your gauge isn't reading high.
#7
06-06-2010, 04:14 PM
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06-06-2010, 06:49 PM
#9
06-07-2010, 04:19 AM
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#10
06-07-2010, 09:35 AM
Tom I put a new one on mine yesterday, dating back to last summer my fan won't lock under heat/load. Brutal trying to tow in CA with the grades. I also flushed out the coolant now for the 2nd time since I'm at 11yrs/250K.
I have a set of calipers and could take some measurements if you want to try and compare my old fan clutch. I went to the cheap tool outlet store place and bought the huge 1 7/8" end wrench for $17 and the Napa Auto store had the big "tongs" for $21. But since you have a couple laying around I'm sure you know how to remove em!
I'm trying to avoid this again:
I have a set of calipers and could take some measurements if you want to try and compare my old fan clutch. I went to the cheap tool outlet store place and bought the huge 1 7/8" end wrench for $17 and the Napa Auto store had the big "tongs" for $21. But since you have a couple laying around I'm sure you know how to remove em!
I'm trying to avoid this again:
#11
06-07-2010, 10:25 AM
#12
06-07-2010, 10:44 AM
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#13
06-07-2010, 03:51 PM
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#14
06-07-2010, 03:57 PM
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Tom I put a new one on mine yesterday, dating back to last summer my fan won't lock under heat/load. Brutal trying to tow in CA with the grades. I also flushed out the coolant now for the 2nd time since I'm at 11yrs/250K.
I have a set of calipers and could take some measurements if you want to try and compare my old fan clutch. I went to the cheap tool outlet store place and bought the huge 1 7/8" end wrench for $17 and the Napa Auto store had the big "tongs" for $21. But since you have a couple laying around I'm sure you know how to remove em!
i have had a set of OTC fan wrenches for almost 20 years now. best $50 i ever spent.
I'm trying to avoid this again:
I have a set of calipers and could take some measurements if you want to try and compare my old fan clutch. I went to the cheap tool outlet store place and bought the huge 1 7/8" end wrench for $17 and the Napa Auto store had the big "tongs" for $21. But since you have a couple laying around I'm sure you know how to remove em!
i have had a set of OTC fan wrenches for almost 20 years now. best $50 i ever spent.
I'm trying to avoid this again:
i did some tests this afternoon with the auto enginuity hooked up, and the trailer on back with a honda on it.
air temp was 78º.
water temp topped out at 166º, oil temp was 145º, and trans fluid temp was 126º
the truck is parked until the new fan clutch goes in it.
#15
06-07-2010, 04:41 PM
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