Engine: Service and Repair
STANDARD PROCEDURE - DETERMINING CYLINDER PRESSURE LOSSIf an increased pressure loss was found with the cylinder leak test, inspect the engine by listening at the cylinder head gasket, air intake area, exhaust, oil fill opening and where injectors and glow plugs enter the cylinder head. Also check the engine coolant in the radiator or expansion reservoir for the formation of bubbles. Possible causes for the pressure loss are:
POSSIBLE CAUSE FOR PRESSURE LOSS
It is possible to pin point the pressure loss of the relevant cylinder by spraying with clean engine oil. Engine oil seals off the gap between the piston and cylinder wall briefly. If a reduced pressure loss now occurs for a short time, the cause is very likely to be the pistons, piston rings or cylinder contact surfaces of the relevant cylinder.
Determining the cause can be falsified by the position of the piston ring joints. If suspicion exists that the loss of pressure is caused by the piston ring joints being positioned directly one above the other, fit the parts to the engine and repeat this test after running the engine for a short time.