4.4 Radiator Cooling Fan

The cooling fan provides additional air flow through the radiator. A faulty cooling fan motor or thermoswitch may be the cause of insufficient air flow and, therefore, overheating. Models covered by this manual have either a single-speed or a two-speed cooling fan.

Most gasoline-engined models built since late 1986 have a radiator cooling fan after-run system, designed to run the cooling fan for up to 15 minutes after the engine is shut off, to aid in restarting a hot engine. A thermoswitch mounted on the cylinder head monitors engine compartment temperature.

In either case, the cooling fan can come on at any time, even if the key is out of the ignition. To avoid personal injury, cooling fan and thermoswitch tests should be performed with extreme caution, and preferably with the engine cold. The tests below simulate a warm engine by electrically bypassing the thermoswitch with a jumper wire. Switching temperatures are given in Table c.

Table c. Radiator Cooling Fan Switching Temperatures