Fan, Fan Clutch Question

[dboyw]

Hello all. Question about fan noise. On Mother's Day I replaced the water pump on the truck. Small leak, but I plan to tour the New England States with fifth wheel in tow this year, so I figured the sooner the better. Coolant was new last year. Coolant filter installed at that time. Changed once, still flowing good. When I took the fan out, I dropped it Broke about a 1 inch piece off of the tip of one of the blades, no other breaks or cracks noted. OK, that's the history.

When driving home the past few days, truck drives and sound normal. When I get off of the highway, and stop for just a few seconds, when I start again it sounds as if the fan clutch is engaging some. Only for about a mile then all sound normal again. I do not remember this happening last year.

Temps have been mid 90*, hazy, hot, humid. AC running on normal but high blower speed. Trans temp is 170s on highway, 180s off, non towing. No actual coolant temp gauge. Soon hopefully.

Any ideas? Just getting concerned since truck is at 140,000 and hopefully many more to come.

Thanks

 

[94f450sd]

dropped it Broke about a 1 inch piece off of the tip of one of the blades

are you talking the plastic fan blade itself or one of the aluminum"fins" on the clutch?if you broke the fan itself i highly suggest that you replace it as it will be out of balance and will cause premature bearing failure in the water pump from vibrations.you may not be used to hearing the fan clutch engage.fords were known for thier abnormally loud cooling fans.nothing to worry about.

 

[CHPMustang]

Dan did you ever get resolve with your fan clutch? Replace the fan and clutch?

Been a couple years since the clutch on our 7.3L really locked up in hot weather,it may need replacing.

 

[dmd]

Last year when going down the freeway at 65mph, an dthe overhead
tem said 111-deg.... The fan clutch locked up...

I will hear the fan on hot days, but only if I have the AC fan low enough.

 

[ZooDad]

Does anyone know of an "easy" way to check the fan clutch ? I have been going round and round with mine. When I spin the fan on the cold motor, there is some tension.

Ideas ?

ZooDad

 

[action4478]

Yea but not easy,,....
Quote:



Fan Clutch Test (7.3L engine)

Spin the fan blade 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 coolant pump pulley+, one of the fan blade retaining bolts and the crankshaft pulley.

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 3600 rpm for 7.3L diesel engines, and aim it at the coolant pump pulley. Adjust the engine speed until the light flash and the coolant 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 2,000 rpm on 6.8L and 7.3L engines.

Turn the engine off.

If the fan blade speed was greater than 2,000 rpm, install a new fan clutch.

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. 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 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 coolant 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 2,850 rpm on 7.3L engines, install a new fan clutch.

 

[CHPMustang]

I recently changed the estimated 100k mile fan clutch on my 5.0L and one way we check is to run the engine to normal by driving around for 10 minutes with the AC on,pull over (shut off engine & remove keys from ignition) pop hood, turn fan by hand and if it turns easily with no or little tension it's time to replace.

I had very little tension compared to cold so I replaced it.Now the AC pours it out like a freezer

I may replace the 7.3L's fan clutch before next spring as we won't be hitting any more 100's this year.

 

[ZooDad]

action4478,
I knew about the "detailed way", but as you stated not that practical.

CHPMustang,
I will definately try out that method.

Thanks

ZooDad