GMC Workshop Manuals
Savana 3500 V8-4.8L (2009)
Powertrain Management > Tune-up and Engine Performance Checks > Compression Check > System Information > Specifications > Page 2587
Compression Check: Testing and Inspection
Engine Compression Test
1. Charge the battery if the battery is not fully charged.
hole. Measure the compression again and record the reading.
10. The minimum compression in any 1 cylinder should not be less than 70 percent of the highest cylinder. No cylinder should read less than 690 kPa
(100 psi). For example, if the highest pressure in any 1 cylinder is 1 035 kPa (150 psi), the lowest allowable pressure for any other cylinder would
Normal - Compression builds up quickly and evenly to the specified compression for each cylinder.
Piston Rings Leaking - Compression is low on the first stroke. Compression builds up with the following strokes, but does not reach normal.
Valves Leaking - Compression is low on the first stroke. Compression usually does not build up on the following strokes. Compression does
If 2 adjacent cylinders have lower than normal compression, and injecting oil into the cylinders does not increase the compression, the cause
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