Additional Information

Once the leakage tester has been connected to one of the cylinders compressed air is fed into that particular cylinder through the built in pressure regulator. Diagnosis is made by observing the amount of leakage that is indicated on the cylinder leakage gauge and by listening for leakage at various points of the cars system. A leakage tester is also known as a leak-down tester.

Location of listening points
Oil Dipstick Tube - for leakage from damaged or worn rings and/or cylinder wall.
Radiator Filler - for cylinder wall cracks or head gasket leakage.
Adjacent Cylinder - for head gasket leakage.
Tail Pipe - for exhaust valve leakage.
Carburettor Air Inlet - for inlet valve leakage.
Fuel  Injection Throttle Body - for inlet valve leakage.

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 broken or cylinder walls are scored excessive leakage will be identified.
It is important that all cylinders have reasonably 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 with low mileage, piston rings may be stuck. Treat engine with quality tune-up oil for a period of time and then re-test before disassembling.
The lower the pitch of the leakage sound, the greater the leak.
To assist with listening use a length of clean hose, or a mechanic’s stethoscope with the probe removed.
When making repeat tests on the same 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.

For further information see pdf document below.

Sealey VSE2020 Cylinder Leakage Tester 2-Gauge Instructions