help on fan mod
Elder User
Joined: Oct 2006
Posts: 635
Likes: 0
From: New York
Here is what the book says on the clutch:
Fan Clutch Test
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:
- 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 1500 rpm until the normal operating temperature has been achieved.
- Adjust the engine speed to 2300 rpm.
- Operate the strobe light at 3000 rpm (on Diesel engines 3600 rpm's) 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 1500 rpm (on Diesel engines 2000 rpm's) at 3000 water pump rpm.
- Turn the engine off.
- If the fan blade speed was greater than 1500 rpm (on Diesel engines 2000 rpm's), replace the fan clutch (8A616).
- Perform Steps 1 through 5 of the Fan Clutch Test—Minimum Speed Requirement.
- NOTE: The temperature 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 3000 rpm (on Diesel engines 3600 rpm's).
- 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 2300 rpm (on Diesel engines 2950 rpm's), replace the fan clutch.
Freshman User
Joined: May 2006
Posts: 32
Likes: 0
02, F250, stock - no mods.
During my last two trips up to the Arizona Rim Country pulling about 4000 and about 110 degrees out, my fan clutch sounded like is was cycling on and off in two second intervals. I've had the truck three years now, been up to the rim in these conditions many times and never experienced this. In the past, it would come on stay on for a minute or more and then dis-engage. Is this normal? Has anyone else experienced this with theirs. Is my going bad?
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During my last two trips up to the Arizona Rim Country pulling about 4000 and about 110 degrees out, my fan clutch sounded like is was cycling on and off in two second intervals. I've had the truck three years now, been up to the rim in these conditions many times and never experienced this. In the past, it would come on stay on for a minute or more and then dis-engage. Is this normal? Has anyone else experienced this with theirs. Is my going bad?
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Posting Guru
Joined: Mar 2007
Posts: 1,425
Likes: 9
FN74, Thanks. You da man. Sorry to here about all your problems on your vacation. I am impressed with your mechanical ablities..and your ability to improvise..Just got back from Klammath Falls last week. Real nice... Country
Posting Guru
Joined: Feb 2007
Posts: 1,146
Likes: 3
From: Bradenton FL
I will post a thread on alot of mods etc ive been doing lately but the fan clutch was one thing i did change. I was told by a ASE PSD mechanic that these clutches have a life expectancy of about a 100k miles and should be changed regardless if there bad or not. Mine was, it was coming on too often at too low of temps. Changed it out and truck is noticeably STRONGER, without that fan pulling on the engine, when that thing is torqued up it steals up to 50hp from u and imagine the mileage ur losing in town spinning that thing. I dont know how much i will gain cause i havent drained my tank yet but i can tell already its going to be noticeable. The fan clutch isnt cheap but i found the cheapest one from fordparts.com, 193$ i would change it even if you think its bad, its worth it.
Posting Guru
Joined: Mar 2007
Posts: 1,425
Likes: 9
Well that's funny yah brought that up. This is somthing I Plan to do also. Regardless if it's bad or not. Just what I think is all. Thanks to you also Benny for the time and the research both that you've done. Big help.
