Compression check (Opel Frontera B)

Checking the compression allows you to draw conclusions about the condition of the engine. Based on the results of the inspection, it is possible to judge the condition of the valves or pistons (piston rings), and also whether the engine has exhausted its service life and is subject to replacement or major repairs.

To check compression on diesel engines, a compression tester with a larger measurement range is required than on gasoline engines.

The pressure data obtained from measurements on each cylinder should not differ by more than 1 bar.

If the pressure in one or more cylinders differs from the pressure in other cylinders by more than 1 bar, this indicates a defect in the valves, wear of the piston rings or working surfaces of the cylinders.

A fully charged battery is a prerequisite for performing a compression test correctly.

Warning! When performing the test, the diesel engine must be in the deck position.

Unscrew the glow plugs (see the relevant chapter).

Disconnect the wiring harness from the engine control unit.

Install the KM-928 adapter in place of the glow plug of cylinder No. 1 and connect a compression gauge to it.



Operate the starter for approximately 4 seconds, the engine speed should be at least 150 min⁻¹.



Check the pressure in each cylinder and write down the obtained values. The pressure values in the cylinders should not differ by more than 1 bar.

Once the test is complete, connect the wiring harness to the engine control unit.

Screw in the glow plugs.