Cylinder Leakage Test (1)

Engine Mechanical - 5.3L L84 or 6.2L L87 | Diagnostic Information and Procedures | Document ID: 5608006 Cylinder Leakage Test Special Tools EN-35667-A Cylinder Head Leakdown Tester Equivalent regional tools: Special Tools

Note

A leakage test may be performed in order to measure cylinder/combustion chamber leakage. High cylinder leakage may indicate one or more of the following conditions: Worn or burnt valves Broken valve springs Stuck valve lifters Incorrect valve lash Damaged piston Worn piston rings Worn or scored cylinder bore Damaged cylinder head gasket Cracked or damaged cylinder head Cracked or damaged engine block

Warning

Refer to Battery Disconnect Warning.

1. Disconnect the battery negative cable. Battery Negative Cable Disconnection and Connection
2. Remove the spark plugs: Gas Engine Ignition Spark Plug Replacement - Left Side Gas Engine Ignition Spark Plug Replacement - Right Side
3. Rotate the crankshaft to place the piston in the cylinder being tested at top dead center (TDC) of the compression stroke.
4. Install the EN-35667-A Cylinder Head Leakdown Tester , or equivalent.

Note

It may be necessary to hold the crankshaft balancer bolt to prevent the crankshaft from rotating.

5. Apply shop air pressure to the EN-35667-A Cylinder Head Leakdown Tester and adjust according to the manufacturers instructions.
6. Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions: Air leakage noise at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring. Air leakage noise at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring. Air leakage noise from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
7. Perform the leakage test on the remaining cylinders and record the values.
8. Install the spark plugs: Gas Engine Ignition Spark Plug Replacement - Left Side Gas Engine Ignition Spark Plug Replacement - Right Side