Tools Required
J 35667-A Cylinder Head Leakdown
Tester
Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing
any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to
the vehicle or its components.
Important: A leakage test may be performed to measure cylinder/combustion chamber
leakage. High cylinder leakage may indicate one or more of the following:
• | Stuck valve lash adjuster |
• | Worn or scored cylinder bore |
• | Damaged cylinder head gasket |
• | Cracked or damaged cylinder head |
• | Cracked or damaged engine block |
- Disconnect the battery ground negative cable.
- Remove the spark plugs. Refer to
Spark Plug Replacement
in Engine Control.
- Rotate the crankshaft to place the piston in the cylinder being
tested at Top Dead Center (TDC) of the compression stroke.
- Install J 35667-A
.
Important: It may be necessary to hold the crankshaft balancer bolt to prevent
the engine from rotating.
- Apply shop air pressure to 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 sounds at the throttle control module or air inlet
hose may indicate a worn or burnt intake valve or a broken valve spring. |
• | Air leakage sounds at the exhaust system tailpipe may indicate
a worn or burnt exhaust valve or a broken valve spring. |
• | Air leakage sounds from the crankcase, oil level indicator tube,
or oil fill tube 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.