Pressure check the cooling system and the cap for leaks. Repair any leaks before proceeding with the diagnosis. Four cylinder engines use an 82°C (185°F) T/STAT. Six cylinder engines use a 91°C (195°F) T/STAT.
Ambient temperatures should be between 13°-38°C (55°-100°F). Place the HVAC controls in the OFF position. Run a cold engine at idle (68°-70°F) for 15-20 minutes before checking the engine temperature.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Pressure check the cooling system and the cap for leaks. Repair any leaks before proceeding with the diagnosis. Four cylinder engines use an 82°C (185°F) T/STAT. Six cylinder engines use a 91°C (195°F) T/STAT. Ambient temperatures should be between 13°-38°C (55°-100°F). Place the HVAC controls in the OFF position. Run a cold engine at idle (68°-70°F) for 15-20 minutes before checking the engine temperature. Is the repair complete? | -- | Go to Step 2 | -- | ||||||||
2 | Verify the engine coolant temperature with a Scan Tool at idle. Is the engine temperature below 85°C (185°F)? | -- | Go to Step 5 | Go to Step 3 | ||||||||
3 | Verify the engine coolant temperature with a Scan Tool at idle. Is the engine coolant temperature between 85-96°C (185-205°F)? | -- | System OK | Go to Step 4 | ||||||||
4 | Verify the engine coolant temperature with a Scan Tool at idle. Is the engine coolant temperature over 96°C (205°F)? | -- | Go to Step 7 | -- | ||||||||
5 | Test the T/STAT for the following conditions:
Are either of these conditions present? | -- | Go to Step 6 | System OK | ||||||||
6 | Replace the T/STAT and replace the T/STAT seal. Refer to Engine Coolant Thermostat Replacement . Is the repair complete? | -- | System OK | -- | ||||||||
7 | Is the radiator inlet hot? | -- | Go to Step 8 | Go to Step 14 | ||||||||
8 | Turn on the heater. Check for hot air at the heater outlets. Is the air hot? | -- | Go to Step 9 | Go to Step 12 | ||||||||
9 | Inspect for blockage in the radiator. Did you find any blockage? | -- | Go to Step 10 | Go to Step 11 | ||||||||
10 | Repair the blockage. Reinspect the radiator with the Scan Tool . Is the repair complete? | -- | System OK | -- | ||||||||
11 | Replace T/STAT. Refer to Engine Coolant Thermostat Replacement . Reinspect the radiator with the Scan Tool . Is the repair complete? | -- | System OK | -- | ||||||||
12 |
Did you find any blockage? | -- | Go to Step 13 | Go to Radiator Hose Replacement in HVAC Systems with AC - Manual | ||||||||
13 | Repair the blockage. Reinspect the radiator with the Scan Tool . Is the repair complete? | -- | System OK | -- | ||||||||
14 | Air may be in the system.
Is the hose hot? | -- | Go to Step 8 | Go to Step 15 | ||||||||
15 | Inspect for blockage in the following locations:
Did you find any blockage? | -- | Go to Step 16 | Go to Step 17 | ||||||||
16 | Repair the blockage. Reinspect the radiator with the Scan Tool . | -- | System OK | -- | ||||||||
17 | Replace T/STAT. Refer to Engine Coolant Thermostat Replacement . Reinspect the radiator with the Scan Tool . Is the repair complete? | -- | System OK | -- |
