For 1990-2009 cars

Step | Operation | Yes | No
--- | --- | --- | ---
DEFINITION: The cooling system is losing coolant either internally or externally.
1 | Do you perform the diagnosis according to Symptoms or other diagnostic table? | Go to Step 2 | Go to Symptoms - Engine Cooling
2 | Repair any present DTC. Did you complete the operation? | 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 . Did you complete the operation? | Go to Step 5 | --
5 | If the engine is suspected to have a coolant leak into a cylinder, the coolant can hydraulically lock the cylinder. Does the engine crankshaft rotate? | Go to Step 6 | Go to Step 23
6 | Engine overheating can cause a loss of coolant. Is the engine overheating? | Go to Step 24 | 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 26 | 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 |

• | 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 25

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:

• | Engine

• | Heater

• | Radiator

• | Surge Tank

Are any of the hoses, clamps or pipes leaking?

Go to Step 19

Go to Step 12

12 | Visually inspect the following components:

• | Core plugs

• | Cylinder Head Gaskets

• | Engine block

• | Intake Manifold

• | Radiator

• | Thermostat

• | Water Pump

• | Surge Tank

• | Surge Tank Cap

Are any of the listed components leaking?

Go to Step 19

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 19

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 20
15 | Pressure test the coolant pressure cap. Refer to Pressure Cap Testing . Does the coolant pressure cap hold pressure? | Go to Step 27 | Go to Step 20
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 21

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 28
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 25 | Go to Step 28
19 | Repair or replace the leaking component. Refer to the appropriate repair. Did you complete the repairs? | Go to Step 28 | --
20 | Replace the coolant pressure cap. Did you complete the repairs? | Go to Step 28 | --
21 | Replace the heater core. Refer to Heater Core Replacement . Did you complete the repairs? | Go to Step 28 | --
22 | Replace the radiator. Refer to Radiator Replacement . Did you complete the repairs? | Go to Step 28 | --
23 | Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate . Did you complete the repairs? | Go to Step 28 | --
24 | Repair the engine overheating condition. Refer to Engine Overheating . Did you complete the repairs? | Go to Step 28 | --
25 | Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber or Coolant in Engine Oil . Did you complete the repairs? | Go to Step 28 | --
26 | Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed . Did you complete the repairs? | Go to Step 28 | --
27 | Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test . Did you complete the repairs? | Go to Step 28 | --
28 | Operate the system in order to verify the repair. Did you find and correct the problem? | System OK | Go to Step 2