| DEFINITION: The cooling system is loosing coolant either internally or externally. |
| 1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - Engine Cooling |
| 2 | Repair any present DTCs. Refer to Diagnostic System Check - Vehicle . Is the action complete? | Go to Step 3 | -- |
| 3 | Inspect the coolant level. Is the coolant at the proper level? | Go to Step 6 | Go to Step 4 |
| 4 | Fill the cooling system to the proper level. Refer to Cooling System Draining and Filling . Is the action complete? | Go to Step 5 | -- |
| 5 | If the engine is suspected to have a coolant leak into a cylinder, the coolant can hydraulically lock the engine. Does the engine crankshaft rotate? | Go to Step 6 | Go to Step 26 |
| 6 | Engine overheating can cause a loss of coolant. Is the engine overheating? | Go to Step 27 | Go to Step 7 |
| 7 | Extended operation with a low coolant level can cause engine internal component failure. Is the engine knocking? | Go to Step 29 | Go to Step 8 |
| 8 | Idle the engine at normal operating temperature. Inspect for heavy white smoke coming out of the exhaust pipe. Is a heavy white smoke present from the exhaust pipe? | Go to Step 9 | Go to Step 10 |
| 9 | Coolant in the exhaust system creates a distinctive, burning coolant odor in the exhaust. Condensation in the exhaust system can cause an odorless white smoke during engine warm up. Does the white smoke have a burning coolant type odor? | Go to Step 28 | Go to Step 10 |
| 10 | With the engine idling, inspect the surge tank. Does the surge tank discharge coolant while the engine is idling? | Go to Step 15 | Go to Step 11 |
| 11 | Visually inspect the hoses, pipes and hose clamps at the following locations: • Coolant surge tank • Heater core • Radiator Are any of the hoses, clamps or pipes leaking? | Go to Step 20 | Go to Step 12 |
| 12 | Visually inspect the following components: • The coolant pressure cap • The core plugs • The cylinder head gaskets • The engine block • The intake manifold • The radiator • The thermostat housing • The water pump Are any of the listed components leaking? | Go to Step 20 | Go to Step 13 |
| 13 | Pressure test the cooling system. Refer to Cooling System Leak Testing . With the cooling system pressurized, visually inspect the components listed in steps 11 and 12. Are any leaks present? | Go to Step 20 | Go to Step 14 |
| 14 | Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure? | Go to Step 16 | Go to Step 21 |
| 15 | Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure? | Go to Step 30 | Go to Step 21 |
| 16 | Inspect for the following conditions: • A coolant smell inside of the vehicle • Coolant in the HVAC module drain tube • Coolant on the vehicle floor covering near the HVAC module Is coolant present? | Go to Step 22 | Go to Step 17 |
| 17 | Inspect the underside of the engine oil fill cap for a gray/white milky substance. Is there a milky substance on under the oil fill cap? | Go to Step 18 | Go to Step 19 |
| 18 | Inspect the engine oil fluid level indicator for a gray/white milky substance. Is there a milky substance on the engine oil fluid level indicator? | Go to Step 28 | Go to Step 19 |
| 19 | Inspect the automatic transmission oil fluid level indicator, if equipped, for a gray/white milky substance. Is there a milky substance on the automatic transmission fluid level indicator? | Go to Step 23 | Go to Step 31 |
| 20 | Repair or replace the leaking component. Is the repair complete? | Go to Step 31 | -- |
| 21 | Replace the coolant pressure cap. Is the repair complete? | Go to Step 31 | -- |
| 22 | Replace the heater core. Refer to Heater Core Replacement . Is the repair complete? | Go to Step 31 | -- |
| 23 | Remove the transmission oil cooler lines from the radiator. Pressure test the cooling system. Refer to Cooling System Leak Testing . Inspect the transmission oil cooler for coolant. Is coolant present? | Go to Step 24 | Go to Step 25 |
| 24 | Replace the radiator. Refer to Radiator Replacement . Is the repair complete? | Go to Step 31 | -- |
| 25 | Install the cooler lines to the radiator. Is the action complete? | Go to Step 31 | -- |
| 26 | Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate . Is the repair complete? | Go to Step 31 | -- |
| 27 | Repair the engine overheating condition. Refer to Engine Overheating . Is the repair complete? | Go to Step 31 | -- |
| 28 | Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber or Coolant in Engine Oil . Is the repair complete? | Go to Step 31 | -- |
| 29 | Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed . Is the repair complete? | Go to Step 31 | -- |
| 30 | Repair the combustion pressure in the cooling system problem. Refer to Coolant in Combustion Chamber . Is the repair complete? | Go to Step 31 | -- |
| 31 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2 |
