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(6) Record the compression pressure on the third revolution. Continue the test for the remaining cylin- (Refer to 9 - ENGINE - SPECIFICATIONS) for the correct engine compression pressures. DIAGNOSIS AND TESTING—CYLINDER 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 All gauge pressure indications should be equal, with no more than 25% leakage. FOR EXAMPLE: At 552 kPa (80 psi) input pres- sure, a minimum of 414 kPa (60 psi) should be main- Refer to CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART below CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART CONDITION POSSIBLE CAUSE CORRECTION AIR ESCAPES THROUGH Intake valve bent, burnt, or not Inspect valve and valve seat. AIR ESCAPES THROUGH Exhaust valve bent, burnt, or not Inspect valve and valve seat. AIR ESCAPES THROUGH Head gasket leaking or cracked Remove cylinder head and inspect. MORE THAN 50% LEAKAGE Head gasket leaking or crack in Remove cylinder head and inspect. MORE THAN 25% LEAKAGE AND Stuck or broken piston rings; Inspect for broken rings or piston. 9 - 220 ENGINE 5.9L AN ENGINE 5.9L (Continued) |