Clean the coolant heater port thoroughly with a clean rag.
Make sure there are no burrs, metal shavings, or sharp edges that can cut the a-ring.
Clean the coolant heater thoroughly with a clean rag.
Make sure the heating element is free of debris and buildup and the sealing area is clean.
Check the coolant heater for cracks on the element.
For flange mounted coolant heaters, check the a-ring for damage. Replace the a-ring if damage is found .
Test the coolant heater resistance. The resistance mustread between 18.2 and 21 .1 ohms.
