School me on fan clutches
- Thread starter svtpower
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So it's working correctly then. It always spins.
After it warms up , it spins a little more freely.
oh
Oh ok because when I read:
To tell if a fan clutch is failing, use these common symptoms.
* The fan clutch locks up, thereby spinning at the same RPM as the water pump. This is obvious by increased fan noise and reduced fuel efficiency. You can test this by grabbing the fan with the engine OFF and trying to turn the fan. If there is excessive resistance, or you cannot spin the fan, the fan clutch should be replaced.
* The fan clutch will not engage and fails to turn the fan. The fan may still spin, but only as a result of centrifugal force from the already spinning pump. If you try to spin the fan with the engine OFF, the fan will spin freely with virtually no resistance. Replace the fan clutch.
* The fan clutch explodes. This is usually caused by severe bearing failure. Fan and fan clutch parts will contact and damage the hood and other under hood engine components (belts, hoses, battery, wiring, radiator, etc.) NOTE: This is almost always due to vehicle owner "laziness" in that one of the two items above had already occurred and were ignored or not periodically inspected.
Taken from http://www.centuryperformance.com/coolingsys.asp (google search)
It made me think mine was bad.
Oh ok because when I read:
To tell if a fan clutch is failing, use these common symptoms.
* The fan clutch locks up, thereby spinning at the same RPM as the water pump. This is obvious by increased fan noise and reduced fuel efficiency. You can test this by grabbing the fan with the engine OFF and trying to turn the fan. If there is excessive resistance, or you cannot spin the fan, the fan clutch should be replaced.
* The fan clutch will not engage and fails to turn the fan. The fan may still spin, but only as a result of centrifugal force from the already spinning pump. If you try to spin the fan with the engine OFF, the fan will spin freely with virtually no resistance. Replace the fan clutch.
* The fan clutch explodes. This is usually caused by severe bearing failure. Fan and fan clutch parts will contact and damage the hood and other under hood engine components (belts, hoses, battery, wiring, radiator, etc.) NOTE: This is almost always due to vehicle owner "laziness" in that one of the two items above had already occurred and were ignored or not periodically inspected.
Taken from http://www.centuryperformance.com/coolingsys.asp (google search)
It made me think mine was bad.
The old rule is that it should freely spin when the engine is off and the engine is cold.
When warmed up (and the engine is shut off), the fan should have greater resistance. I generally get a half turn or less out of it with a decent spin (edit: this is when the clutch itself is hot).
It has a bimetallic spring which regulates silicone fluid inside the hub (viscous coupling). If the silicone leaks out (noted as dirty oil around the hub), this is an indication that it's on the outs.
Good luck.
When warmed up (and the engine is shut off), the fan should have greater resistance. I generally get a half turn or less out of it with a decent spin (edit: this is when the clutch itself is hot).
It has a bimetallic spring which regulates silicone fluid inside the hub (viscous coupling). If the silicone leaks out (noted as dirty oil around the hub), this is an indication that it's on the outs.
Good luck.
My fan clutch spins a lot louder when the engine is dead cold than it does once it's fully warmed up. I don't know if that's normal or not, it's suposedly a year old (bought it used)... my old Blazer with a clutch fan did the same thing though.
My original fan clutch in the Stang was really erattic so who knows if I've ever had a properly functioning clutch fan on any of my cars...
My original fan clutch in the Stang was really erattic so who knows if I've ever had a properly functioning clutch fan on any of my cars...
The fan will rotate full-time. The speed at which it rotates is determined by how much the clutch hub is engaged which is directly proportional to the engine temp. When it does fully lock-up, it will be a 1:1 ratio of the water pump speed. At this point it will basically sound like a Mack truck as I like to call it.
Easy way to tell if it is working correctly is if you have ever heard this sound (you will have if you drive a car with one in the summer and the A/C blowing for sure), then it will sound like this all the time including when the engine is first started and it is cold. It should only make that sound normally when the engine temp becomes hot enough, but the fan will always turn with the water pump at a variable slip ratio until lock-up occurs.
Easy way to tell if it is working correctly is if you have ever heard this sound (you will have if you drive a car with one in the summer and the A/C blowing for sure), then it will sound like this all the time including when the engine is first started and it is cold. It should only make that sound normally when the engine temp becomes hot enough, but the fan will always turn with the water pump at a variable slip ratio until lock-up occurs.
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