Engine Cooling System: NVH GMC Savana G2500

Noise

Fan noise is sometimes evident when the following normal conditions exist

1. The clutch is engaged for maximum cooling.
2. The engine has been running for 15-60 seconds after start-up. After this time, the clutch can redistribute the silicone fluid back to the normal disengaged operating conditions.

Fan noise or an excessive roar may occur when the following conditions exist

1. The engine speed is 2,500 RPM or higher.
2. The clutch assembly is locked up due to an internal failure.

Rotate the fan (1).

With the engine off, replace the clutch (2) if the following conditions exist

1. The fan cannot be rotated by hand.
2. The fan produces a rough, grating feel as it turns. Refer to «Fan Clutch Replacement»(ref-186629-S20719799892005083000000) .

Scheme 5

If the fan assembly is loose, inspect the fan assembly for wear. Replace the fan assembly as necessary.

Observe the tip of the fan blade for lateral movement. Lateral movement occurs under various temperature conditions. A lateral movement measuring 6.5 mm (1/4 in) is normal. This amount of movement is not cause for replacement of the assembly.