Pinpoint Test 1: Loss Of Coolant
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PINPOINT TEST 1: LOSS OF COOLANT- HYBRID
Normal Operation
The engine cooling system is a closed system that provides for coolant expansion and contraction and also changes in pressure as coolant warms and cools with engine operation. Various gaskets, seals, hoses and clamps are used to 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.For vehicle/engine specific information, see - Engine Cooling Description/Operation.
Possible Causes
- Coolant hoses or tubes
- Hose clamps
- Thermostat O-ring seal or gasket
- Coolant pump O-ring seal or gasket
- Thermostat housing
- Heater control valve (if equipped)
- Radiator
- Transaxle fluid cooler (in radiator)
- Pressure relief cap
- Coolant pump leaking from weep hole
- Auxiliary coolant pump (if equipped)
- Heater core
- Heated throttle body or heated throttle body adapter (if equipped)
- Coolant crossover manifold assembly (if equipped)
- Engine gaskets
- Oil cooler (if equipped)
- Degas bottle (if equipped)
- Coolant expansion tank (if equipped)
- Heated positive crankcase ventilation (PCV) (if equipped)
- Fuel pressure regulator coolant bowl (if equipped)
- Cylinder block core plugs (if equipped)
- Cylinder head core plugs (if equipped)
- Block heater (if equipped)
Diagnostic Procedure
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.
