G 30 Van V8-454 7.4L VIN N TBI (1995)
Fan Clutch: Testing and Inspection
Engine Overheating
1. Start with cool engine to ensure complete fan clutch disengagement.
2. If fan and clutch assembly free wheels with no drag (revolves more than five times when spun by hand), replace clutch. If clutch performs properly
with slight drag, proceed to following step.
3. Position thermometer so it is located between fan blades and radiator, noting the following:
a. Insert thermometer sensor through one of existing holes in fan shroud or place between radiator and shroud. It may be necessary to drill a 3/16
inch hole in fan shroud to insert thermometer.
b. Check for adequate clearance between fan blades and thermometer sensor before starting engine, as damage could occur.
4. With thermometer in position, cover radiator grill sufficiently to induce high engine temperature.
5. Start engine, then turn on air conditioning and operate at 2000 RPM.
6. Observe thermometer reading when clutch disengages, noting the following:
a. It will take approximately five to ten minutes for temperature to become high enough to allow engagement of fan clutch. This will be indicated
by a 5-15 degrees F drop in thermometer reading.
b. If clutch did not engage between 150-195 degrees F, unit should be replaced. Ensure fan clutch was disengaged at beginning of test.
c. If no sharp increase in fan noise or temperature drop was observed and fan noise level was constantly high from start of test to 190 degrees F,
unit should be replaced. Do not continue this test past thermometer reading of 190 degrees F to prevent engine overheating.
7. As soon as clutch engages, remove radiator grill cover and turn A/C off to assist in engine cooling. Run engine at approximately 1500 RPM.
8. After several minutes, fan clutch should disengage as indicated by reduction in fan speed and roar. If fan clutch fails to function as described,
replace it.
