Test J: Insufficient, Erratic Or No Heat
WARNING: This page is about a different car, the 1999 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
- Check For Proper Coolant Level
Check coolant level with engine hot and cold. If coolant level is not okay, replace coolant and check for leaks. If coolant level is okay, go to next step. - Check For Hot Coolant To Heater Inlet
Start and run engine to normal operating temperature. Check for hot water to heater core inlet hose by feeling heater hose at inlet tube to heater core. If hose is too hot to handle, go to step 4) . If hose is cool to touch, check cooling system and repair as needed. Ensure inlet hose flow restrictor is in place and is not damaged. Repair as necessary. - Check For Cooling System Leaks
Ensure coolant reservoir is filled to proper level. Perform cooling system pressure checks. If all components of cooling system hold pressure, go to next step. If leak is found, pressure test heater core and make repairs or replace components as needed. - Check For Hot Coolant At Heater Outlet
Ensure engine is running at normal operating temperature. Carefully feel heater core outlet hose. If heater core outlet hose is cool or cold, test heater core for plugged or restricted condition. If outlet hose is hot, go to TEST C .