CLAS AC 0118 Manuel D'instructions page 6

AC 0118
CYLINDER LEAK DETECTOR TESTER
Helpful suggestions
• If 100% or excessive leakage shows on gauge the cylinder may not be at TDC on the compression stroke. Check
to ensure that the valves are closed. Always try to position piston at TDC for uniform results.
• If rings are brocken or cylinder walls are scored excessive leakage will be identi ed.
• It is importnat that all cylinders have resonably uniform readings (as in compression testing). Differences in excess
of 15% indicate excessive leakage.
• Large engines tend to leak more than small engines.
• If leak is excessive on a vehicle wih low mileage, piston rings my be stuck. Treat engine with quality tune-up oil
for a period time and then re-test before disassembling.
• The lower the pitch of the leakage sound, the grater the leak.
• To assist with listening use a lengh of clean hose, or a mechanic's sthetoscope with the probe removed.
• When making repaet tests on the sema cylinder, variations in the piston position and engine temperature can
cause gauge readings to differ by up to 10%.
• If an engine has multiple faults (such as worn rings and burned valves) the tester may indicate only the most
serious fault.
Note: There is always some leakage past the piston rings. As a result you will always hear some leakage when
listening to the dipstick tube.
Low compression reading on some cylinders
Use oil in cylinder to see if rings are worn
If compression increase, rings and/or
cylinder wall are worn
If compression does not rise, do a cylin-
der leakage test to determine source of
problem
USE
High relative compression readings and
relatively equal cylinder readings
But, if excessive axhaust emissions, lack
of power, poor performance or poor fuel
Do an AC 0118 test
Determine source of problem
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consumption
Lower relative compression readings, one
or more cylinder lower
Do an AC 0118 test
Determine source of problem