Testing Cylinders For Leaks

NOTE: Numbers in parentheses ( ) indicate a component or tool in the associated illustration.

1. Warm up engine to normal operating temperature and remove air cleaner.
2. Record radio settings and disconnect ground cable at battery.
3. Remove spark plugs.
4. Open (leave open) cap (1) on expansion reservoir (2).
5. Adjust coolant to correct level.
6. Take off oil filler cap (3).
7. Connect cylinder leak tester (5) to compressed air system.
8. Calibrate tester (5).
9. Screw connection hose (5a) into first spark plug hole.
10. Rotate (piston of cylinder to be tested) at crankshaft with setting device to ignition TDC.
11. Connect connection hose (5a) to tester.
12. Pressureize compression chamber with approximately 5 bar.

NOTE: When doing this, do not rotate the crankshaft; if necessary, lock crankshaft in position to prevent it turning

13. Open throttle valve by hand.
14. Read pressure loss at tester (5) (in %).
- Determine whether the pressure escapes through intake manifold, exhaust, oil filler opening, spark plug hole of adjacent cylinder or through coolant opening.
15. Test all cylinders in firing order (1-5-3-6-2-4).

NOTE: After spraying oil onto the piston crown, it is possible to determine whether the leak exists at the piston rings or at the valves, or at the cylinder head gasket.

Specifications:
- Total pressure loss: 25% maximum
- At valve and cylinder head gasket: 10% maximum
- At piston and piston rings: 20% maximum

Piston at TDC with marking index on vibration damper: (refer to the illustration)
Crank Pulley Mark Piston at TDC
OT = TDC 1 or 6
b = 120° 2 or 5
a = 240° 3 or 4

16. Reverse procedure, noting the following:
- Encode radio.
- On Model 140, normalize power windows.