The fan clutch on the NAS Defender 110 is an automatic device and an integral part of the cooling system. When the engine is cool or else at a normal operating temperature, the fan clutch will partially disengage the engine's mechanically driven radiator cooling fan. When the engine temperature rises above normal settings, the fan will then become fully engaged, maintaining and even lowering engine temperature.

NAS 110's fan clutch is generally quite reliable but will eventually need replacement like any other automotive part. Symptom include overheating when idling, poor air conditioning performance since the fan also cools the air conditioner's condenser found directly in front of the radiator. At times a failed fan clutch may draw the air at a very high rate, so in the cold weather the heating system will blow out lukewarm air restricting the heating system from delivering sufficient hot air.

Clutch fan replacement: Replacement is relatively simple if you know what you are doing. The fan clutch is simply sandwiched between the fan and the connecting shaft, located between the radiator and the water pump. Simply unbolt the clutch holding bolts to remove both clutch and fan. Replacement clutch is then installed and the fan re-attached. It's a good idea to flush all coolant and put in a new thermostat at the same time.

If your Defender drives without overheating on hi-way, yet overheats off-hi-way and in traffic, then it's most likely time to replace the fan clutch. RoversNorth will have your replacement fan clutch in stock.