Diagnostic Routine A

Diagnostic Routine A

Diagnostic Overview

Loss of Coolant

Normal Operation and Fault Conditions

The engine cooling system is a closed system providing for coolant expansion and contraction, as well as changes in pressure as coolant warms and cools with engine operation. Various gaskets, seals, hoses and clamps contain coolant within the cooling system and keep other fluids and contaminants from entering the cooling system.

Coolant loss can be attributed to either external or internal leaks anywhere within the cooling system, including:

- Coolant hoses or tubes

- Hose clamps

- Coolant pump O-ring seal

- Thermostat housing gasket

- Thermostat housing

- Radiator

- Pressure relief cap

- Coolant pump leaking from weep hole

- Heater core

- Engine gaskets

- Degas bottle

- Cylinder block core plugs

- Cylinder head core plugs

- Block heater (if equipped)

REFER to System Diagram .

Special Tool(s)






Pinpoint Test

WARNING: Always allow the engine to cool before opening the cooling system. Do not unscrew the coolant pressure relief cap when the engine is operating or the cooling system is hot. The cooling system is under pressure; steam and hot liquid can come out forcefully when the cap is loosened slightly. Failure to follow these instructions may result in serious personal injury.

1. CARRY OUT INSPECTION AND VERIFICATION

1. Carry out Inspection and Verification Initial Inspection and Diagnostic Overview. REFER to Symptom Chart: Engine Cooling Symptom Related Diagnostic Procedures.

Were any concerns found?






2. CHECK THE ENGINE COOLANT LEVEL

NOTE: Allow the engine to cool before checking the engine coolant level.

1. Ignition OFF.

2. Visually inspect the engine coolant level at the coolant expansion tank.

Is the engine coolant level within specifications?






3. PRESSURE TEST THE ENGINE COOLING SYSTEM

1. Pressure test the engine cooling system. REFER to Cooling System Pressure Test Cooling System Pressure Test.

Does the engine cooling system leak?






4. CHECK THE ENGINE COOLANT FOR AN INTERNAL LEAK

1. Inspect the engine coolant in the coolant expansion tank for signs of engine oil.

Is engine oil evident in the coolant?






5. CHECK THE ENGINE OIL FOR COOLANT

1. Remove the oil level indicator from the engine.

Is coolant evident in the oil?






6. CHECK THE COOLING SYSTEM FOR COMBUSTION GASES

1. Using 105R0110 (-) , follow the instructions supplied with the tester and check the coolant for combustion gases.

Are combustion gases present?