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Ensure the battery is completely charged and the engine starter motor is in good operating condition. (1) Clean the spark plug recesses with compressed air. (2) Remove the spark plugs. the engine with the engine starter motor for three (6) Record the compression pressure on the third revolution. Continue the test for the remaining cylin- Refer to Engine Specifications for the correct engine compression pressures. CYLINDER HEAD GASKET FAILURE DIAGNOSIS A cylinder head gasket leak can be located between adjacent cylinders or between a cylinder and the • Possible indications of the cylinder head gasket leaking between adjacent cylinders are: • Loss of engine power • Engine misfiring • Poor fuel economy • Possible indications of the cylinder head gasket leaking between a cylinder and an adjacent water • Engine overheating • Loss of coolant • Excessive steam (white smoke) emitting from exhaust • Coolant foaming CYLINDER-TO-CYLINDER LEAKAGE TEST To determine if an engine cylinder head gasket is leaking between adjacent cylinders, follow the proce- CYLINDER-TO-WATER JACKET LEAKAGE TEST WARNING: USE EXTREME CAUTION WHEN THE VISUAL TEST METHOD With the engine cool, remove the coolant pressure cap. Start the engine and allow it to warm up until If a large combustion/compression pressure leak exists, bubbles will be visible in the coolant. COOLING SYSTEM TESTER METHOD WARNING: WITH COOLING SYSTEM TESTER IN PRESSURE BUILT UP, BY CONTINUOUS ENGINE OPERATION, MUST BE RELEASED TO A Install Cooling System Tester 7700 or equivalent to pressure cap neck. Start the engine and observe the CHEMICAL TEST METHOD Combustion leaks into the cooling system can also be checked by using Bloc-Chek Kit C-3685-A or CYLINDER COMBUSTION PRESSURE LEAKAGE The combustion pressure leakage test provides an accurate means for determining engine condition. Combustion pressure leakage testing will detect: ing) • Leaks between adjacent cylinders or into water jacket • Any causes for combustion/compression pressure loss WARNING: DO NOT REMOVE THE RADIATOR CAP BURNS FROM HOT COOLANT CAN OCCUR. Check the coolant level and fill as required. DO NOT install the radiator cap. Start and operate the engine until it attains nor- mal operating temperature, then turn OFF the Remove the spark plugs. er’s instructions. The shop air source for testing Perform the test procedure on each cylinder accord- ing to the tester manufacturer’s instructions. While 9 - 146 5.9L ENGINE DN DIAGNOSIS AND TESTING (Continued) |