1989 Chevy Truck Radiator fan always engaged

Tiny
LUSTERMUSIC
  • MEMBER
  • 1989 CHEVROLET TRUCK
  • V8
  • 2WD
  • AUTOMATIC
  • 55,000 MILES
I recently noticed that my radiator fan was remaining on all the time. As a result, the fan clutch actually got worn out to the point of wobbling really bad, and I replaced it. It operated properly for about 100 miles (Engaged sometimes, but most of the time was disengaged). Now, it's back on all the time. My thought was that maybe the engine is running too hot, so I topped off the radiator(it took about a gallon of coolant). It's still on all the time. The fan clutch is completely mechanical with a thermostatic spring which engages and disengages the clutch according to direct temp. This tells me that my engine is still running hotter than it should. Could this be a faulty water pump? Or thermostat? Something is preventing my engine from totally receiving it's cooling resources. (Note: I have not overheated at all, and the temp gauge looks normal all of the time) Also, there was one occasion when the temp gauge did rise rapidly at a red light, but then fell again just before overheating (this was before replacing the fan clutch). That only happened once to my knowledge (could have happened again, but didn't notice it). Any ideas as to why my engine is hot enough to keep the fan clutch engaged constantly, but never hot enough to overheat?
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Tuesday, October 12th, 2010 AT 5:10 PM

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Tiny
RASMATAZ
  • MEMBER
Hi lustermusic, Welcome to 2carpros and TY for the donation

Check the fan clutch operation-while engine is cold- when you spin it the fan will turn a little and when engine is at full operating temperature it will resist the spin-if its function properly

Check and test the thermostat or replace it
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Tuesday, October 12th, 2010 AT 6:51 PM
Tiny
LUSTERMUSIC
  • MEMBER
Could it be a possibility that I am not getting total flow of coolant through the system due to a blockage? Making it impossible for the engine to cool down to a temperature which would trigger the mechanical fan clutch to disengage when it's supposed to? I am holding a consistent temperature, it's just that it's high enough to not allow the fan clutch to disengage. Also, the fan runs at engine(water pump) speed(fully engaged) even immediately after cold start. It's on 100% of the time, and it's a brand new fan clutch which I just installed not 2 weeks ago. This is exactly what the old fan clutch was doing, that is until it nearly flew off the post into my radiator(which is why I had to replace it). It actually damaged the shroud, but I caught it in time.
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Tuesday, October 12th, 2010 AT 7:09 PM
Tiny
RASMATAZ
  • MEMBER
Go to this link and learn how the fan clutch works for better explanation you beginning to make me think its electrically operated fan clutch

http://www.aa1car.com/library/cooling_fan_clutch.htm
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Tuesday, October 12th, 2010 AT 7:21 PM

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