Caution! To check the compression pressure, it is necessary to use a compression tester for diesel engines.
The engine condition can be checked by measuring the compression pressure in the cylinders. If this check is carried out regularly, it is possible to know in advance the beginning of engine wear, without waiting for the moment when wear manifests itself in low engine efficiency.
1. Using a compression gauge with an adapter, check the compression pressure in the engine cylinders.
2. Before checking the compression pressure, make sure the battery is charged and in good condition. The air filter must be clean and the engine must be warmed up to normal operating temperature. Remove the glow plugs before checking. To prevent the engine from starting during the check, remove the fuel cut-off relay.
3. Install the adapter with the compression tester into the glow plug installation hole.
4. Turn the engine over with the starter. After turning the crankshaft 1 or 2 revolutions, the compression pressure should increase to the maximum and then stabilize. Record the maximum result obtained. Check the remaining cylinders in the same way.
5. The compression pressure in all cylinders should not differ by more than two units. Note that the compression value should increase rapidly on a serviceable engine. Low compression pressure on the first revolution of the crankshaft, followed by a gradual increase in pressure on subsequent revolutions, indicates wear of the piston rings. Low pressure on the first revolution of the crankshaft, which increases slightly later, indicates loose valves, a broken cylinder head gasket, or cracks in the cylinder head.
6. After performing the compression pressure test, install the fuel shut-off relay and install the glow plugs.
Material taken from a web resource: MERCEDESMAN.ru