1304720129 | Genuine Cummins® Cooling Fan Clutch

The fan clutch is used on selected:

• Cummins M11
• Cummins ISM
• Some N14 applications
• Selected industrial Cummins engines using the same cooling fan drive configuration.

Typical Vehicle & Equipment Applications

These engines were installed in a wide variety of heavy-duty vehicles and equipment, including:

• Kenworth T600, T800, W900
• Peterbilt 357, 377, 378, 379
• Freightliner FLD, Century, Classic XL
• Western Star 4900 Series
• Volvo heavy-duty trucks equipped with Cummins M11/ISM engines
• International trucks with Cummins M11 or ISM engines
• Transit and coach buses
• Fire trucks
• Construction equipment
• Industrial power units and generators

Engages the fan when the engine is hot to pull air through the radiator, cooling down the coolant and engine.
Disengages when the engine is cool, allowing it to warm up faster and avoid overcooling.

2. Improve Fuel Efficiency

A constantly spinning fan adds drag on the engine.
A fan clutch reduces this load by spinning the fan only when needed, saving fuel.

3. Reduce Engine Wear

Less mechanical load means less strain on:
Belts
Bearings
Water pump
It also helps extend the life of the cooling system components.

4. Lower Noise

When disengaged, the fan spins at a lower speed or coasts, reducing the loud “roaring” noise typical of engine fans.

5. Support Emissions Compliance

Proper temperature control helps engines run at optimal efficiency and stay within emissions limits.
Modern electronically controlled fan clutches are managed by the ECM and tied into aftertreatment systems.

1. Overheating Engine

One of the most obvious signs.
If the fan clutch doesn’t engage, the fan won't spin fast enough to cool the radiator.
Most noticeable when:
Idling in traffic
Towing heavy loads
Driving uphill or in hot weather

2. Excessive Fan Noise (Constant Roaring)

If the fan clutch is stuck in the “on” position, the fan may spin at full speed all the time.
Sounds like a loud roar, especially on startup or acceleration.
This causes reduced fuel efficiency and increased wear.

3. Poor Fuel Economy

A locked-on or constantly spinning fan consumes more power from the engine.
This increases fuel consumption unnecessarily.

4. Fan Spins Freely (Even When Hot)

With the engine off and warm, manually spinning the fan should meet some resistance.
If the fan spins freely with no drag, the clutch may be worn out or failed.

5. A/C System Underperformance

A bad fan clutch may prevent proper airflow across the condenser, especially at low speeds.
You might notice weak A/C cooling when the vehicle is stopped or idling.

6. Warning Lights or Trouble Codes

Newer trucks (especially with electronic fan clutches) may trigger:
Check Engine Light
Cooling system fault
Fan clutch solenoid or ECM-related codes