DEFINITION: The cooling system is losing coolant either internally or externally.

Do you perform the diagnosis according to Symptoms or other diagnostic table?

Go to Step 2

Go to Symptoms - Engine Cooling

Repair any present DTC.

Did you complete the operation?

Go to Step 3

--

Inspect the coolant level.

Is the coolant at the proper level?

Go to Step 6

Go to Step 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

--

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

Engine overheating can cause a loss of coolant.

Is the engine overheating?

Go to Step 24

Go to Step 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

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

Does the white smoke have a burning coolant type odor?

Go to Step 25

Go to Step 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

Visually inspect the hoses, pipes and hose clamps at the following locations:

Are any of the hoses, clamps or pipes leaking?

Go to Step 19

Go to Step 12

Visually inspect the following components:

Are any of the listed components leaking?

Go to Step 19

Go to Step 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

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

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

Inspect for the following conditions:

Is coolant present?

Go to Step 21

Go to Step 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

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

Repair or replace the leaking component. Refer to the appropriate repair.

Did you complete the repairs?

Go to Step 28

--

Replace the coolant pressure cap.

Did you complete the repairs?

Go to Step 28

--

Replace the heater core. Refer to Heater Core Replacement .

Did you complete the repairs?

Go to Step 28

--

Replace the radiator. Refer to Radiator Replacement .

Did you complete the repairs?

Go to Step 28

--

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

--

Repair the engine overheating condition. Refer to Engine Overheating .

Did you complete the repairs?

Go to Step 28

--

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

--

Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed .

Did you complete the repairs?

Go to Step 28

--

Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test .

Did you complete the repairs?

Go to Step 28

--

Operate the system in order to verify the repair.

Did you find and correct the problem?

System OK

Go to Step 2