During a compression test, a cylinder shows lower readings than expected. Technician A squirts a tablespoon of oil into the cylinder and the compression raises. He says this indicates a problem with the rings. Technician B says a running compression test should be about one-quarter of that of a cranking compression test. Which technician is correct?
A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Question

Quizplus · Accepted Answer

If adding oil to the cylinder causes the compression to raise, it indicates that there is a problem with the rings. This is because the oil helps to create a better seal between the rings and the cylinder walls, temporarily increasing compression. Technician B is incorrect as there is no set ratio of running compression test to cranking compression test.

During a Compression Test, a Cylinder Shows Lower Readings Than