For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Were you sent here from Symptoms? | Go to Step 2 | Go to Symptoms - Engine Cooling
2 | Repair any present DTCs. Refer to Diagnostic System Check - Engine Cooling . Is the action complete? | Go to Step 3 | --
3 | Inspect the coolant level. Is the coolant at the proper level? | Go to Step 5 | 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 28
6 | Engine overheating can cause a loss of coolant. Is the engine overheating? | Go to Step 29 | Go to Step 7
7 | Extended engine operation with a low coolant level can cause engine internal component failure. Is the engine knocking? | Go to Step 31 | Go to Step 8
8 |

1. Idle the engine at normal operating temperature.
2. 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 |

1. Condensation in the exhaust system can cause an odorless white smoke during engine warm up.
2. Coolant in the exhaust system creates a distinctive, burning coolant odor in the exhaust.

Does the white smoke have a burning coolant type odor?

Go to Step 30

Go to Step 10

10 | With the engine idling, inspect the coolant recovery system. Does the coolant recovery system discharge coolant while the engine is idling? | Go to Step 15 | Go to Step 11
11 | Visually inspect the cooling system hoses, pipes and hose clamps at the following locations:

• | Coolant reservoir

• | Heater

• | Radiator

Are any of the hoses, clamps or pipes leaking?

Go to Step 20

Go to Step 12

12 | Visually inspect the following components:

• | Coolant pressure cap

• | Coolant reservoir

• | Core plugs

• | Cylinder head gaskets

• | Engine block

• | Intake manifold

• | Radiator

• | Thermostat

• | Water pump

Are any of the listed components leaking?

Go to Step 20

Go to Step 13

13 |

1. Pressure test the cooling system. Refer to Cooling System Leak Testing .
2. Visually inspect the components listed in steps 11 and 12 again.

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 32 | 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 vehicles floor covering under the HVAC module.

Is coolant present?

Go to Step 22

Go to Step 17

17 | Inspect the underside of the oil fill cap for a gray/white milky substance. Is there a milky substance 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 fluid level indicator? | Go to Step 23 | 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 26 | Go to Step 32
20 | Repair or replace the leaking component. Refer to the appropriate repair procedure. Is the repair complete? | Go to Step 32 | --
21 | Replace the coolant pressure cap. Is the repair complete? | Go to Step 32 | --
22 | Replace the heater core. Refer to Heater Core Replacement in HVAC. Is the repair complete? | Go to Step 32 | --
23 |

1. Remove the engine oil cooler lines from the radiator.
2. Pressure test the cooling system. Refer to Cooling System Leak Testing .
3. Inspect the engine oil cooler for coolant.

Is coolant present in the engine oil cooler?

Go to Step 24

Go to Step 27

24 |

1. Replace the radiator. Refer to Radiator Replacement .
2. Service the engine oil and filter. Refer to Engine Oil and Oil Filter Replacement in Engine Mechanical.

Is the repair complete?

Go to Step 32

--

25 |

1. Remove the transmission oil cooler lines from the radiator.
2. Pressure test the cooling system. Refer to Cooling System Leak Testing .
3. Inspect the transmission oil cooler for coolant.

Is coolant present in the transmission oil cooler?

Go to Step 26

Go to Step 27

26 |

1. Replace the radiator (TRANS COOLER). Refer to Radiator Replacement .
2. Service the automatic transmission. Refer to Engine Coolant/Water in Transmission in Automatic Transmission.

Is the repair complete?

Go to Step 32

--

27 | Install the cooler lines to the radiator. Is the repair complete? | Go to Step 32 | --
28 | Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate in Engine Mechanical. Is the repair complete? | Go to Step 32 | --
29 | Repair the engine overheating condition. Refer to Engine Overheating . Is the repair complete? | Go to Step 32 | --
30 | Repair the engine internal coolant leak. Refer to the appropriate repair procedure. Is the repair complete? | Go to Step 32 | --
31 | Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed in Engine Mechanical. Is the repair complete? | Go to Step 32 | --
32 | Operate the system in order to verify the repair. Does the system operate correctly? | System OK | Go to Step 2