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Home › Ford › 1989 › Bronco 5.0 N, Standard, M5OD-R2 › Repair and Diagnosis › Engine Mechanical › Engine Cooling Fan › Thermostatic Controlled Fan › Testing

Thermostatic Controlled Fan: Testing

  1. When engine overheats or insufficient cooling caused by air conditioning (if equipped) or other components occurs, fan drive and thermostatic control must be tested. Start with cool engine to ensure complete fan drive disengagement. Cover radiator grille to induce high engine temperature.
  2. Start engine. Operate at 2000 RPM and turn on air conditioning (if equipped). Fan noise will increase when fan drive engages. It will take 5-10 minutes for fan to engage. While operating engine under these conditions, observe temperature gauge or light to prevent overheating. If vehicle overheats, remove cover from radiator grille.
  3. As soon as drive engages, remove cover from radiator grille and turn off air conditioning (if equipped). After several minutes, fan drive should disengage. This can be determined by reduction in fan speed and noise. If fan drive fails to function as described, it should be replaced.
  4. Fan drive should also be replaced if shaft seal is leaking fluid. If noise or roughness can be felt while turning fan by hand, replace drive. Frozen unit must be replaced.
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