The difference in pressure between the individual engine cylinders can be up to 5.0 bar. If one or more cylinders have a pressure difference of more than 5.0 bar, this indicates a malfunction of the valves, wear of the piston rings or the working surfaces of the cylinders. If the wear limit is reached, the engine must be repaired or replaced.
When checking compression, the temperature of the engine oil must be at least +30°C. The oil filter should be at hand temperature, warm up the engine if necessary. The engine temperature must not be too high as otherwise, when unscrewing the spark plugs, the threads in the cylinder head can be damaged.
1. Switch off the ignition.
2. Remove nozzles.
3. Disconnect the fuel shut-off valve plug.
Attention! If the plug is not disconnected, fuel will flow out when the engine is turned over.
4. Check compression pressure.
5. Install injectors.
6. Plug in the plug on the CO reduction valve.
Engine | RPM when checking | Compression pressure in bar | |
New | wear limit | ||
2.0 l Diesel | 200 | 30 – 33 | 25 |