Measurement Procedure

WARNING: This page is about a different variant/trim than selected.

Check Compression for all cylinders:

Fig 1: Compression Gauge

Courtesy of GENERAL MOTORS COMPANY

Install the EN-51749 gauge (1, 2) into the spark plug bore for the cylinder that is being checked.

NOTE:

Engine revs at least 300/min.

Crank the engine (approx. 4 seconds).
Compare the compression values.
Maximum pressure differential 100 kPa (14.5 psi)
Transfer the compression tester to the next spark plug hole.
Repeat the process for the remaining cylinders.