Testing cylinders for leaks - RA01001200150X(01-0150)
WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.
Preceding work
Open hood, raise to vertical position (01-0080)
Operation no. of operation texts and work units or standard texts and flat rates
DATA
| Total pressure loss max. | 25 % |
| At valves and cylinder head gasket | max. 10 % |
| At pistons and piston rings max. | 20 % |
TIGHTENING TORQUE SPECIFICATION
| Spark plugs | 25 |
Special tools
COMMERCIALLY AVAILABLE TOOL
| Cylinder leak tester | eg. | Bosch, EFAW 210 A Sun, CLT 228 |
Testing
- Warm engine up to operating temperature.
- Disconnect ground cable at battery.
- Remove air cleaner together with mass air flow sensory (09-0015) .
- Remove viscous fan clutch (20-3120) .
- Blow out spark plug recesses with compressed air.
- Unscrew spark plugs (15-1031) .
- Adjust coolant to correct level (arrow) and leave filler opening on coolant reservoir open.
- Take off oil filler cap.
- Connect cylinder leak tester to a compressed air system and calibrate tester.
- Screw connection hose into first spark plug hole, fit on whistle.
- 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 following 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.
Marking number Pistons at TDC 0 1 and 6 60 7 and 12 120 2 and 5 180 8 and 11 240 3 and 4 300 9 and 10 - Fit on connection hose of tester and pressurize combustion chamber (approx. 5 bar).
The crankshaft must not be rotated when performing this step.
- Open throttle valves by hand.
- Read off pressure loss at tester (in %).
- 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.
- 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 after short period.