Checking Compression Pressure
- Before checking engine compression, check the engine oil level. Also check that the starter motor and battery are all in normal operating condition.
- Start the engine and wait until engine coolant temperature reaches 80-95°C (176-205°F).
- Turn off engine and disconnect the spark plug cables.
- Remove the spark plugs.
- Crank the engine to remove any foreign material in the cylinders.
- Insert the compression gauge into the spark plug hole.
- Depress the accelerator pedal to open the throttle fully.
- Crank the engine and read the gauge.
- Standard value: 1500 kPa (15 Kg/cm2 , 218 psi)
- Limit: 1400 kPa (14 Kg/cm2 , 203 psi)
- Repeat steps 6 to 8 over all cylinders, ensuring that the pressure differential for each of the cylinders is within the specified limit.
- Limit: Max. 100 kPa (1.0 kg/cm2 , 14 psi) between cylinders
- If a cylinder's compression or pressure differential is outside the specification, add a small amount of oil through the spark plug hole, and repeat steps 6 to 9.
- If the addition of oil makes the compression to rise, it is likely that there may be wear between the piston ring and cylinder wall
- If compression remains the same, valve seizure, poor valve seating or a compression leak from the cylinder head gasket are all possible causes.
Tightening torque
- Spark plug: 20-30 N.m (200-300 kg.cm, 14-22 lb.ft)