GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 VUE - FWD 🢒 Engine 🢒 Engine Cooling 🢒 Cylinder Leakage Test

Testing Procedure

Tools Required

J 35667-A Cylinder Head Leakdown Tester

With the use of air pressure, a cylinder leakage test will aid in the diagnosis. Use the cylinder leakage test in conjunction with the engine compression test in order to isolate the cause of leaking cylinders.

    Caution: Refer to Battery Disconnect Caution in the Preface section.

  1. Disconnect the negative battery cable.
  2. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 3.0L.
  3. Install the J 35667-A .
  4. Measure each cylinder on the compression stroke, with both valves closed.

    5. Important: Hold the crankshaft balancer bolt in order to prevent piston movement.

  5. Apply air pressure, using the J 35667-A . Refer to the manufacturer's instructions.
  6. Record the cylinder leakage readings for each cylinder.

    7. Important: 

       • Normal cylinder leakage is from 12 to 18 percent.
       • Make a note of any cylinder with more leakage than the other cylinders.
       • Any cylinder with 30 percent leakage or more requires service.

  7. Inspect the 4 primary areas in order to properly diagnose a leaking cylinder.
  8. If air is heard from the intake or exhaust system, perform the following procedure:
    9. • Remove the valve rocker arm cover of the suspect cylinder head.
       - Ensure that both valves are closed.
       - Inspect the cylinder head for a broken valve spring.
    • Remove and inspect the suspect cylinder head. Refer to Cylinder Head Cleaning and Inspection .
  9. If air is heard from the crankcase system at the crankcase oil filler tube, perform the following procedure:
    10. 9.1. Remove the piston from the suspect cylinder.
    9.2. Inspect the piston and connecting rod assembly. Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection .
    9.3. Inspect the engine block. Refer to Engine Block Cleaning and Inspection .
  10. If bubbles are found in the radiator, perform the following procedure:
    11. • Remove and inspect both cylinder heads. Refer to Cylinder Head Cleaning and Inspection .
    • Inspect the engine block. Refer to Engine Block Cleaning and Inspection .
  11. Remove the J 35667-A .
  12. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 3.0L.

    13. Caution: Refer to Battery Disconnect Caution in the Preface section.

  13. Connect the negative battery cable.