2008 Ford Ranger with the 3.0 Two months ago I replaced the fan clutch and the coolant temp sensor to address this issue. It did help a little, especially when the car was idling in the driveway, it would not "spool-up" so loudly. However when I am about 30% or more acceleration the fan will get really loud, like a semi-truck, with the fan spinning at a very loud and high rate.

I confirmed the coolant temps (from a ODB reader) never exceed 197f. The coolant was replaced 6 months ago. The temps here when this does this are high 70's to high 80's.

I can't understand what causes the fan to run so darn high - is it just the fan clutch?

  • Sounds like the clutch for sure is not disengaging and therefore its spinning up as the engine accelerates. You said you replaced the fan clutch, did you do that yourself or had a workshop do it?
    – NetServOps
    Commented Jul 30, 2021 at 5:46
  • with the engine off can you easily spin the fan by hand,you should be able to rotate the fan easily with your little finger. Commented Aug 31, 2021 at 8:38

1 Answer 1


My understanding of fan clutches is the bimetallic temperature sensor in the center front clutch body regulates fan operation; cold air entering the front grille would not have the fan turning much and as temps increase, fan engagement increases for more airflow. Some have adjustable sensors for fine tuning while others are fixed. Is the replacement an oem part or aftermarket one? If aftermarket, it may be an incorrect one or faulty. It's presumed fan clutches aren't needed at speed as sufficient airflow would cool the ac condenser coil and radiator. At low speed and traffic where airflow is much lower, sensed heat should enable the fan for higher airflow. This fan clutch may be stuck in closed position where engagement is at 100% hence the loud fan noise at higher engine rpm.

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