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Helpful hints
•
If 100 % or excessive leakage values are shown on the tester, the cylinder might not be in the
DTC on the compression stroke. Make sure that all valves are closed. Always try to set the
piston to DTC to have uniform readings.
•
With piston rings broken or cylinder walls scored, excessive leakage will be shown.
•
It is important that all cylinders have reasonably uniform readings (as for compression testing).
Differences of more than 15 % indicate excessive leakage.
•
Big engines tend to leak more than small ones.
•
If leakage is excessive on a vehicle that has a low mileage/kilometrage, the piston rings might
be stuck. Treat the engine with high-quality tune-up oil for a period, then re-test it before disas-
sembling.
•
The lower the pitch of the leakage sound is, the greater is the leakage.
•
When performing a listening test, use a piece of clean hose or a mechanic's stethoscope with
its probe removed.
•
When performing re-tests on the same cylinder, variations in the piston position and engine
temperature can cause gauge values to differ by up to 10 %.
•
If an engine has multiple faults (such as worn rings and burnt valves), the tester may only indi-
cate the most serious fault.
Note!
There is always slight leakage on the piston rings. As a result, you will always hear some
leakage sounds when listening to the dipstick tube.
Troubleshooting
Possible cause
Low compression values on some cylinders
High compression values and relatively equal cyl-
inder values
Lower compression values, on or more cylinders
lower than others
Important Note:
Reproduction and any commercial use (of parts) of this operating manual, requires a written permission
of WilTec Wildanger Technik GmbH.
© by WilTec Wildanger Technik GmbH
http://www.WilTec.de
http://www.aoyue.eu
http://www.teichtip.de
Proposed solution
Use oil in cylinder to see if rings are worn.
If compression increases, rings and/or cylinder
wall are worn.
If compression does not increase, perform a cylin-
der leakage test to determine the cause of the
problem.
With excess of exhaust emissions, lack of power,
poor performance, or poor fuel consumption, per-
form a cylinder leakage test to determine the
cause of the problem.
Perform a cylinder leakage test to determine the
cause of the problem.
Item 51726
Page 6
12 2021-1
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