Special Tools
WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
- EN-35667 - A Cylinder Head Leakdown Tester
- EN-51749 Compression Gauge Tester Kit
Equivalent regional tools: Special Tools
Procedure
A leakage test is performed in order to measure cylinder/combustion chamber leakage. High cylinder leakage may indicate one or more of the following:
- Worn or burnt valves
- Broken valve springs
- Stuck valve lifters
- Incorrect valve lash/adjustment
- Damaged piston
- Worn piston rings
- Worn or scored cylinder bore
- Damaged cylinder head gasket
- Cracked or damaged cylinder head
- Cracked or damaged engine block
- Disconnect the battery negative cable.
- Remove the intake manifold cover.
- Remove the ignition coils from all cylinders.
- Remove the spark plugs.
- Rotate the crankshaft to place the piston in the cylinder being tested at top dead center (TDC) of the compression stroke.
- Thread the EN-51749 Compression Gauge Tester Kit into the spark plug hole.
- Install the EN-35667 - A Cylinder Head Leakdown Tester or equivalent.
- Apply shop air pressure to the EN-35667 - A Cylinder Head Leakdown Tester 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 body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring
- Air leakage sounds at the exhaust system tailpipe that 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 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.
- Install the spark plugs.
- Install the ignition coils.
- Install the intake manifold cover.
- Connect the battery negative cable.
WARNING:
Refer to Battery Disconnect Warning .
CAUTION:
Only turn the engine in a CLOCKWISE direction as viewed from the crankshaft balancer. Counterclockwise rotation may result in the timing chain jumping a tooth, causing poor running, DTCs, or severe engine damage.
NOTE:
It may be necessary to hold the crankshaft balancer bolt to prevent the engine from rotating.