Crossfire SRT-6 V6-3.2L SC VIN N (2005)
Compression Check: Testing and Inspection
DIAGNOSIS AND TESTING - CYLINDER COMPRESSION PRESSURE TEST
The results of a cylinder compression pressure test can be utilized to diagnose several engine malfunctions. Ensure the battery is completely charged
and the engine starter motor is in good operating condition. Otherwise the indicated compression pressures may not be valid for diagnosis purposes.
1. Check the engine oil level and add oil if necessary.
2. Drive the vehicle until engine reaches normal operating temperature. Select a route free from traffic and other forms of congestion, observe all
traffic laws, and accelerate through the gears several times briskly.
3. Disconnect all of the ignition coils from the spark plugs.
4. Remove one spark plug from each cylinder of the engine. As the spark plugs are being removed, check electrodes for abnormal firing indicators;
fouled, hot, oily, etc. Record cylinder number of spark plug for future reference.
5. Make sure the throttle blade is fully open during the compression check.
6. Insert compression gauge into the #1 spark plug hole in the cylinder head.
7. Crank the engine until maximum pressure is reached on the gauge. Record this pressure as #1 cylinder pressure.
8. Repeat the previous step for all of the remaining cylinders.
9. Compression should not be less than 689 kPa (100 psi) and not vary more than 25 percent from cylinder to cylinder.
10. If one or more cylinders have an abnormally low compression pressure, repeat the compression test.
Note: The recommended compression pressures are to be used only as a guide to diagnosing engine problems. An engine should not be
disassembled to determine the cause of low compression unless some form of malfunction is present.
11. If the same cylinder or cylinders repeat an abnormally low reading on the second compression test, it could indicate the existence of a problem in
the cylinder in question.
