Horton Fan Clutch – Troubleshooting

While numerous truckers will watch out for their engine coolants, the state of their Horton fan clutches is frequently ignored until a problem arises.

But a working Horton fan clutch can control cooling system temperatures precisely and will guarantee that your fan is just drawn in when it’s required – activating the fan with a temperature-controlled indoor regulator that triggers a solenoid to apply or release compressed air. The end result is lower fuel consumption, a faster response at upper and lower temperature thresholds, and lower exhaust emissions with reduced white smoke and less internal engine deposits.

Fans are required depending upon the speed and load of your specific engine. But when they do run, there is a cost. A typical 32-inch multi-blade fan on a high-horsepower diesel truck can draw 25 to 30 hp. (The fan’s diameter, speed, number of blades and pitch all affect the actual power draw.)

Horton Fan Clutch

Horton Fan Clutch Systems and Troubleshooting

Horton fan clutch systems have a patented System Sentry. It goes about as an early cautioning fuse to alarm the administrator of possibly harming impact to the Horton fan clutch framework. When the system’s fuse blows, it indicates an overload condition. Instead of replacing the fuse each time, look for the problem.

One of the main reasons that a fuse blows can be traced to overheating due to a slipping fan clutch hub.

Check for:

  1. Fan clutches that have been installed and used beyond their load capacity. Manufacturers set the specs for engine cooling fans to meet the engine’s cooling requirements.


  1. Incorrect air pressure to the fan clutch. Air supplies of less than 90 psi (621 KPa) can cause the fan clutch to slip as it attempts to disengage the clutch. This can be traced to leaks in the airline or air pressure that is sourced (drawn off) for other air operated accessories. One good example would be using the compressed air on a cement mixer to pressurize the onboard water supply tank. Or when pumping off the load from a tanker. Keep in mind that heavy-duty fan clutches require between 90-120 psi to operate correctly.


  1. The improper conditioning of a new fan clutch. A new fan clutch friction disc lining is somewhat like a new brake lining. It needs to be broken in. As the rough surface of a new fan clutch disc is engaged and disengaged a number of times, the surface will become smoother. This provides more surface contact and the capability of handling higher torques. You can burnish the new disc by setting the truck idle to approximately 1,500 rpm. Then you can manually engage and disengage the fan clutch between 15 to 20 times. Allow 10-15 seconds for each application of the disc.


To manually activate the clutch, you simply need to plumb a compressed air line directly to the fan hub. Then use a toggle switch to apply and release the air. This allows the internal spring to compress and release the clutch, with air vented to reapply it.