Compression Test
WARNING: This page is about a different car, the 2003 Saturn LW200 and 2003 Saturn L200. However, it is still accessible from the selected car via links, so may be relevant.
- Conduct the following steps in order to check cylinder compression:
- Engine should be at room temperature.
- Disconnect wiring from ignition module.
- Remove spark plugs.
- Throttle body valve should be wide open.
- Battery should be at or about full charge.
- For each cylinder, crank engine through 4 compression strokes.
- The lowest reading cylinder should not be less than 70 percent of the highest reading.
- No cylinder reading should be less than 100 psi (689 kPa)
The results of a compression test will fall into the following categories:
- Normal - Compression builds up quickly and evenly to specified compression on each cylinder.
- Piston Rings - Compression is low on the first stroke, tends to build up on following strokes, but does not reach normal. Compression improves considerably with the addition of oil.
- Valves - Compression is low on the first stroke, does not tend to build up on the following strokes, and does not improve much with the addition of oil. Use about 3 squirts from a plunger-type oiler.