Sebring V6-2.5L VIN N (1997)
Compression Check: Testing and Inspection
1. Before inspection, check that the engine oil, starter and battery are normal. Also, set the vehicle to the following condition:
^
Engine coolant temperature: 80 - 95° C (176 - 203° F)
^
Lights*, electric cooling fan and all accessories: OFF
^
Transaxle: Neutral (P range on vehicle with A/T)
2. Disconnect the spark plug cables.
3. Remove all spark plugs.
4. Disconnect the MFI relay (ASD relay) connector to prevent a spark.
5. Cover the spark plug hole with a shop towel etc., and after the engine has been cranked, check that no foreign material is adhering to the shop towel.
WARNING: Keep away from the spark plug hole when cranking. If compression is measured with water, oil, fuel, etc., that has come
from cracks inside the cylinder, these materials will become heated and will gush out from the spark plug hole, which is dangerous.
6. Set compression gauge to one of the spark plug holes.
7. Crank the engine with the throttle valve fully open and measure the compression pressure. The standard value at engine speed of 250 - 400 RPM is
1,275 kPa (185 psi). The maximum at engine speed of 250 - 400 RPM is minimum 959 kPa (139 psi).
8. Measure the compression pressure for all the cylinders, and check that the pressure differences of the cylinders vary a maximum of 98 kPa (14 psi).
NOTE: The limit value can be derived by calculating the difference between the maximum and minimum values for the compression pressure and
dividing this value by the maximum value.
9. If there is a cylinder with compression or a compression difference that is outside the limit, pour a small amount of engine oil through the spark plug
hole, and repeat the operations in steps 7 and 8.
a. If the compression increases after oil is added, the cause of the malfunction is a worn or damaged piston ring and/or cylinder inner surface.
b. If the compression does not rise after oil is added, the cause is a burnt or defective valve seat, or pressure is leaking from the gasket.
10. Connect the MFI relay (ASD relay) connector.
11. Install the spark plug and spark plug cable.
12. Use the scan tool to erase the diagnostic trouble codes.
NOTE: This will erase the diagnostic trouble code resulting from the MFI relay (ASD relay) being disconnected.
* In vehicles for Canada, the headlight, tail light, etc. will remain lit even when the lighting switch is turned OFF but this is no problem.
