Testing Cylinders For Leaks

PRECEDING WORK
Open hood, raise to vertical position.

TESTING
1 Warm engine up to operating temperature.
2 Disconnect ground cable at battery.
3 Remove air cleaner together with mass air flow sensor.
4 Remove viscous fan clutch.
5 Blow out spark plug recesses with compressed air.





6 Unscrew spark plugs.





7 Adjust coolant to correct level (arrow) and leave filler opening on coolant reservoir open.
8 Take off oil filler cap.
9 Connect cylinder leak tester to a compressed air system and calibrate tester.
10 Screw connection hose into first spark plug hole, fit on whistle.





11 Turn piston of cylinders to be tested to ignition TDC with socket wrench, special tool 001 589 65 09 00. The respective pistons are in ignition TDC, or in TDC position, when the illustrated markings on the vibration damper are aligned with the TDC pointer.

NOTE:
The markings at 60°, 180° and 300° on the vibration damper are affixed as of July 1992 (phased-in). If an engine is not provided with these markings, determine the respective TDC position by means of the spark plug hole and the piston.





12 Fit on connection hose of tester and pressurize combustion chamber (approximately 5 bar). The crankshaft must not be rotated when performing this step.
13 Open throttle valves by hand.
14 Read off pressure loss at tester (in %).
15 Listen to determine whether the pressure escapes through the intake manifold, exhaust, oil filler opening, spark plug hole of adjacent cylinder or coolant filler opening.
16 Test all the cylinders in the firing order (1-12-5-8-3-10-6-7-2-11-4-9).





NOTE:
It is possible that the piston ring gaps of individual pistons are positioned immediately above each other and therefore falsify the result of the test. In cases of doubt, run engine and recheck the cylinders for leaks a after short period.


DATA






TIGHTENING TORQUE






SPECIAL TOOLS















COMMERCIALLY AVAILABLE TOOL