Will a Compression Test Show Bad Rings?

A compression test reveals the condition of your engine's valves, its valve seats, and piston rings and whether these parts are wearing evenly. Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.

Can a compression test tell you if you have a ring problem?

Cylinder compression tests are performed to identify any cylinders that have poor compression. If a cylinder has low compression, perform a wet compression test to indicate whether it's a bad valve, head gasket, or worn piston rings causing the problem.

What type of compression test do you perform to see if rings are bad?

Leakdown Test

This is done by inserting compressed air (around 100 psi) into the cylinder at TDC and then measuring how much is lost from the seals (there will always be some).