Bravada 2WD L6-4.2L VIN S (2002)
Compression Check: Testing and Inspection
Cylinder Leakage Test
Cylinder Leakage Test
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Tools Required
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J 35667-A Cylinder Leakdown Tester
With the use of air pressure, a cylinder leakage test will aid in the diagnosis. The cylinder leakage test may be used in conjunction with the engine
compression test, to isolate the cause of leaking cylinders.
Caution: Refer to Battery Disconnect Caution in Service Precautions.
1. Remove the battery ground (negative) cable.
2. Remove the spark plugs.
3. Install J 35667-A.
4. Measure each cylinder on the compression stroke, with the valves closed.
Important: It may be necessary to hold the crankshaft balancer bolt, to prevent piston movement.
5. Apply air pressure, using J 35667-A. Refer to the manufacturer's instructions.
6. Record the cylinder leakage readings for each cylinder.
Important:
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Normal cylinder leakage is from 12 to 18 percent.
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Make a note of any cylinder with more leakage than the other cylinders.
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Any cylinder with 30 percent leakage or more requires service.
7. Inspect the four primary areas, to properly diagnose a leaking cylinder.
8. If air is heard from the intake or exhaust system, perform the following procedure:
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Remove the camshaft cover.
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Ensure the valves are closed.
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Inspect the cylinder head for a broken valve spring.
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Remove the cylinder head and inspect.
9. If air is heard from the crankcase system at the crankcase (oil filler tube), perform the following procedure:
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Remove the piston from the suspect cylinder.
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Inspect the piston and connecting rod assembly.
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Inspect the engine block.
10. If bubbles are found in the radiator, perform the following procedure:
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Remove the cylinder head and inspect.
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Inspect the engine block.
11. Remove the J 35667-A.
12. Install the spark plugs.
13. Install the battery ground (negative) cable.
