Test A: Loss of Coolant

Pinpoint Test A: Loss of Coolant

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, 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 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)
^ Engine coolant temperature (ECT) sensor (if equipped)

PINPOINT TEST A: LOSS OF COOLANT

WARNING: Never remove the pressure relief cap under any conditions while the engine is operating or hot. Failure to follow these instructions could result in personal injury or damage to the cooling system or engine. To avoid having scalding hot coolant or steam blow out of the cooling system, use extreme care when removing the pressure relief cap. Wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly. Step back while the pressure is released from the cooling system. When you are certain all the pressure has been released, (with a cloth) turn and remove the pressure relief cap. Failure to follow these instructions may result in serious personal injury.

A1-A6:

A7: