Crankcase and cylinder head,  OM617

Checking cylinders for leaks



01—015 Checking cylinders for leaks




Total pressure loss
On valves and cylinder head gasket
On pistons and piston rings
max. 25 % max. 10% max. 20 %


Special tool


Socket 27 mm, 1/2″ square socket for rotating engine
om617 - 0014-1.jpg
000 589 65 09 00
Screw fitting for glow plug bore
617 589 03 21 00


Conventional tool


Cylinder leak tester
e.g. made by Bosch, EFAW 210 A made by SUN, CLT 228




1 Run engine up to operating temperature.


2 Unscrew pencil element glow plugs.


3 Remove air cleaner cap.


4 Remove oil filler plug.


5 Remove radiator cap and top up coolant.


6 Enter screw fitting into glow plug bore of 1st cylinder.
om617 - 0014-2.jpg


«5?J –


01.8-015/1 F2




7   Set piston of 1st cylinder to ignition TDC. For this purpose, rotate engine at crankshaft by means of tool combination.
8   Connect cylinder leak tester to a compressed air system. Calibrate tester.
9   Screw connecting hose of tester to screw fitting. Crankshaft should not rotate.
om617 - 0015-1.jpg




10    Read pressure loss on tester.
11    Check by listening whether pressure escapes via intake pipe, exhaust, oil filler cap, glow plug bore of adjacent cylinder or radiator cap.
12   Check all cylinders in ignition sequence.
om617 - 0015-2.jpg


Note: There is the possibility that the piston ring gaps of individual pistons are directly one above the other, so that the test result will be misrepresented.
When in doubt, continue running vehicle and check cylinders for leaks once again later on.


01.8-015/2 F2