Fan clutch
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Senior Member
Joined: Oct 2003
Posts: 4,920
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From: Washington
Fan clutch
i replaced my fan clutch because it seemed to have a slight amount of play and i didnt feel comfortable with it having some play in it.
anyways, cut to the chase.
new clutch seems to work when its not suppose to, i start the truck on a cool morning, like 40-50 degrees and its sucking air full blast until i take off and hit like 35mph or 2.5k rpm. hasnt gotten hot enough lately to make it pull air like its suppose to when its hot.
any ideas why or how to fix this? its driving my dad up the wall, hes about to replace it with electric fans, and i see it as a waste of money.
anyways, cut to the chase.
new clutch seems to work when its not suppose to, i start the truck on a cool morning, like 40-50 degrees and its sucking air full blast until i take off and hit like 35mph or 2.5k rpm. hasnt gotten hot enough lately to make it pull air like its suppose to when its hot.
any ideas why or how to fix this? its driving my dad up the wall, hes about to replace it with electric fans, and i see it as a waste of money.
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Joined: Jun 2001
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Actually, that is perfectly normal operation. The fan clutch works with a silicone fluid. There is some sort of bi-metallic temperature-sensitive valve in the clutch that controls the flow of the silicone fluid. I don't know the details, but basically when underhood temps are cool enough, the valve sends the fluid a certain way in the clutch that disengages the fan and lets the fan freewheel or nearly so. When underhood temps rise high enough, the valve sends the fluid another way, which tightens up the clutch and spins the fan full speed.
However, to address your concern, it is normal for the silicone fluid to "settle" overnight in such a way that engages the clutch for a few minutes after a cold startup until the fluid can be redistributed in its normal pattern based on the underhood temperatures. The "roaring" sound produced by the fan can be annoying to some people, but the "cold-startup/fan engaged" situation is perfectly normal on most any vehicle with a belt driven fan and a fan clutch. I'm pretty sure the FSM even mentions this annoying but harmless occurance.
SM
'01 Scew
4.6 4x2
However, to address your concern, it is normal for the silicone fluid to "settle" overnight in such a way that engages the clutch for a few minutes after a cold startup until the fluid can be redistributed in its normal pattern based on the underhood temperatures. The "roaring" sound produced by the fan can be annoying to some people, but the "cold-startup/fan engaged" situation is perfectly normal on most any vehicle with a belt driven fan and a fan clutch. I'm pretty sure the FSM even mentions this annoying but harmless occurance.
SM
'01 Scew
4.6 4x2
Thread Starter
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Senior Member
Joined: Oct 2003
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From: Washington
yeah but the only reason i asked is because its on every start up, even when the trucks been run 5 miles to school, then started it back up to go to the store across the street. its literally every start, not just the first one of the day. just curious of why its every start is all.
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Joined: Aug 2000
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From: San Jose, California, U.S.A.
There have been reports of fan clutches that have done what you describe. Most of these claims are from people who have replaced them with non OEM flan clutches. Go electric just for the coolness factor.
Jesse
Jesse
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Joined: Dec 2001
Posts: 537
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From: Booneville, Mississippi
When I put a napa fan clutch(let me say that I love most napa parts) on my 97 it did the same thing. My buddies would say that they could hear the clutch before they heard my exhaust.I replaced it with the flex a lite dual electric fans til i sold the truck when i put it back on. I now how the fans on my 03 L.