Test A: Loss of Coolant
Pinpoint Test A: Loss of CoolantNormal 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, refer to Engine Cooling in Description and Operation.
This pinpoint test is intended to diagnose the following:
^ 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
^ Transmission fluid cooler (in radiator) (if equipped)
^ Pressure relief cap
^ Coolant pump leaking from weep hole
^ Auxiliary coolant pump (if equipped)
^ Heater core
^ Heated throttle body (TB) or heated TB 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 PCV (if equipped)
^ Fuel pressure regulator coolant bowl (if equipped, natural gas engine)
^ Cylinder block core plugs (if equipped)
^ Cylinder head core plugs (if equipped)
^ Block heater (if equipped)
^ Engine coolant temperature (ECT) sensor (if equipped)
^ EGR cooler(s) (diesel only)
^ EGR valve (diesel only)
