Checking Compression Pressure

WARNING: This page is about a different car, the 2004 Hyundai Santa Fe and 2003 Hyundai Santa Fe. However, it is still accessible from the selected car via links, so may be relevant.

Before checking the 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 the engine coolant temperature reaches 80-95°C (176~205°F).
Stop the 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 : 1,200kpa(12.2 kg/cm² , 170psi)

Limit :

1,050kpa(10.7kg/cm² , 149psi)

Fig 1: Checking Compression Gauge
Courtesy of HYUNDAI MOTOR CO.
Repeat steps 6 to 8 for all cylinders, making sure that the pressure difference for each of the cylinders is within the specified limit.
Limit : Max. 100kpa (1.0 kg/cm² , 14psi) 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.
1. If the addition of oil causes the compression to rise, it is possible that the piston ring is worn.
2. If the compression remains the same, valve seizure, poor valve seating or a compression leak in the cylinder head gasket are all possible causes.

Tightening torque

Spark plug : 20 ~ 30 Nm (200 ~ 300 kg.cm, 14 ~ 22 lb.ft)