Initial Inspection and Diagnostic Overview
INSPECTION AND VERIFICATION1. Verify the vehicle owner's original concern by operating the engine cooling system to duplicate the concern.
Mechanical Or Electrical Concerns:
2. Inspect to determine if one of the Mechanical Or Electrical Concerns apply.
3. Perform the system pressure test.
a. Turn engine OFF.
WARNING: Never remove the pressure relief cap under any conditions while the engine is operating. Failure to follow these instructions could result in damage to the cooling system or engine and/or personal injury. To avoid having scalding hot coolant or steam blow out of the cooling system, or radiator coolant recovery reservoir, use extreme care when removing the pressure relief cap from a hot cooling system or radiator coolant recovery reservoir. Wait until the engine has cooled, then wrap a thick cloth around the pressure relief cap and turn it slowly until the pressure begins to release. Step back while the pressure is released from the cooling system. when certain all the pressure has been released, (still with a cloth) turn and remove pressure relief cap.
b. Check engine coolant level.
c. Remove the pressure relief cap from the radiator coolant recovery reservoir to relieve pressure in cooling system. Inspect filler neck sealing gasket for foreign material between gasket and cap diaphragm, making sure that pressure cap and radiator coolant recovery reservoir threaded surfaces are not damaged. Clean and inspect the Pressure Relief Cap. Reinstall pressure relief cap.
d. Disconnect the electrical connector from the water temperature indicator sender unit and remove the water temperature indicator sender unit.
NOTE: With the pressure relief cap installed and the cooling system pressure relieved, only a small amount of coolant will be lost when the water temperature indicator sender unit is removed.
Rotunda Radiator/Heater Core Pressure Tester 014-R1052:
e. Install the adapter fitting from Rotunda Radiator/Heater Core Pressure Tester 014-R1052 or equivalent (male thread on one end and a hose connector on the other end to accommodate the tester hose) tightly in place of the water temperature indicator sender unit.
f. Attach the pressure pump and gauge to the adapter fitting and pressurize the cooling system to the pressure relief cap lower limit.
g. Observe the pressure gauge reading for approximately two minutes. Pressure should not drop during this time.
h. If the pressure reading drops within two minutes, pressure test the pressure relief cap.
i. If the pressure relief cap does not hold pressure, remove and wash the pressure relief cap in clean water to dislodge all foreign particles from the gaskets. Recheck the sealing surface in the radiator coolant recovery reservoir filler neck. Replace components as required.
j. Pressurize the engine cooling system as outlined in Step f (using a pressure relief cap that operates within the specified upper and lower pressure limits) and observe the gauge reading for approximately two minutes. Pressure should not drop during this time.
k. RESULTS: If the pressure drops, check for leaks at the engine to heater core hoses, engine-to-radiator hoses, water thermostat housing gasket, radiator and heater core, and other areas. Any leaks which are found must be corrected and system rechecked.
l. If the system holds pressure, proceed to Step m.
m. Release system pressure by loosening the pressure relief cap and removing the adapter. Check engine coolant level and fill as necessary with correct coolant mixture and install water temperature indicator sender unit.
4. If the concerns remain after the inspection, determine the symptoms and go to the Symptom Chart. Symptom Related Diagnostic Procedures