Engine Overheats (Replace Engine Fan Clutch Assembly
| Subject: | Engine Overheats (Replace Engine Fan Clutch Assembly) |
| Models: | 1997-98 Chevrolet and GMC T-Series Medium Duty Models with 3116/3126 Caterpillar® Diesel Engines Equipped with 24 and 26 Inch Fan Blades |
This bulletin is being revised to change Model information and part numbers. Please discard Corporate Bulletin Number 86-62-08A (Section 6 - Engine).
Condition
Some owners/operators may comment that the engine overheat lamp illuminates and that the temperature gauge is in the red zone. The audible overheat alarm may also sound.
Cause
The fan clutch calibration may be incorrect. This may cause the fan clutch to engage too late. This will cause the audible alarm to sound.
The disengaged speed of the clutch may be too slow. This may cause the fan clutch sensor to become unresponsive due to lack of air flow.
Correction
A new fan clutch has been developed to correct the condition. This fan clutch has the following features:
| • | The calibration is revised. |
| • | The disengage speed is higher. This ensures proper cycling of the cooling fan. |
| • | The engagement has been revised to on/off instead of modulating. |
Replace the engine fan clutch assembly using the appropriate part number listed below. Refer to Fan Replacement (Fan Clutch) in Engine Cooling in the appropriate Medium Duty Service Manual for fan clutch replacement procedures.
Parts Information
P/N | Description | Quantity |
|---|---|---|
15044771 | Clutch Asm., Fan Blade (26" Fan Blade) | 1 |
15044772 | Clutch Asm., Fan Blade (24" Fan Blade) | 1 |
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
J9220 | Clutch Asm., Fan - R&R or Replace | Use published labor operation time |
