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Home >> Saturn >> 2003 >> Ion 1 Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> Preliminary Inspection & Adjustments >> Mechanical Inspection >> Test Procedure
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Test Procedure

  1. Disconnect the negative battery cable.
  2. Remove the spark plugs.
  3. Rotate the crankshaft to place the piston in the cylinder being tested at Top Dead Center (TDC) of the compression stroke.
  4. Install the Cylinder Head Leakdown Tester (J 35667-A), or equivalent.
  5. Apply shop air pressure to the Cylinder Head Leakdown Tester and adjust according to the manufacturers instructions. It may be necessary to hold the crankshaft balancer bolt to prevent the engine from rotating.
  6. 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 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.
  7. Perform the leakage test on the remaining cylinders and record the values.
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