The optional engine coolant heater (RPO KO5) is designed to warm the coolant in the engine block area for improved starting in very cold weather -29°C (-20°F). The use of coolant heaters helps reduce fuel consumption when a cold engine is warming up. The engine coolant heater coils are rated at 600 watts. The engine coolant heater coils operate from 110 volt AC external power supply.

The coolant heater consists of two electrical heating elements fastened to the left and right sides of the engine block. These heating blocks are precisely machined. A weather shield on the cord is provided to protect the plug when not in use.

Perform the following if the coolant heater fails to heat the coolant:

1. Test the AC external power source for 110 volt AC.
2. Test the coolant heater cord for an open or short to ground. Refer to Circuit Testing in Wiring Systems.
3. Test the coolant heater for continuity.
4. Inspect the harness connectors for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.