Tools Required
J 35667-A Cylinder Head Leakdown Tester
or equivalent
Important: 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 scored cylinder bore |
• | Damaged cylinder head gasket |
• | Cracked or damaged cylinder head |
• | Cracked or damaged engine block |
Caution: Refer to Battery Disconnect Caution in the Preface section.
- Disconnect the battery ground negative cable.
- Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls -
6.0L.
- Rotate the crankshaft to place the piston in the cylinder being tested
at top dead center (TDC) of the compression stroke.
- Install the
J 35667-A or equivalent.
Important: It may be necessary to hold the crankshaft
balancer bolt to prevent the crankshaft from rotating.
- Apply shop air pressure to the
J 35667-A
and adjust according to the manufacturers instructions.
- 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. |
- Perform the leakage test on the remaining cylinders and record the values.