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Cylinder Combustion Pressure Leakage

  1. Disconnect negative battery cable. Remove spark plugs. Install Cylinder Head Leakdown Tester (J-35667 A). Measure each cylinder on compression stroke, with both valves closed.
    2. NOTE: Hold crankshaft balancer bolt in order to prevent piston movement.
  2. Apply air pressure to cylinder leakdown tester. Record cylinder leakage readings for each cylinder. Any cylinder with 25 percent leakage or more requires service.
  3. Inspect following primary areas in order to properly diagnose a leaking cylinder.
    • If air is heard from intake or exhaust system, remove valve rocker arm cover of suspect cylinder head. Ensure that both valves are closed. Inspect cylinder head for a broken valve spring or remove and inspect suspect cylinder head.
    • If air is heard from crankcase system at crankcase oil filler tube, remove piston from suspect cylinder. Inspect piston and connecting rod assembly. Inspect engine block.
    • If bubbles are observed in radiator, remove and inspect both cylinder heads. Inspect engine block.
  4. After performing test, remove leakdown tester. Install spark plugs and reconnect negative battery cable.
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