During a cylinder leak test, what should be done if one cylinder shows 80% leakage?

When one cylinder shows 80% leakage during a cylinder leak test, repeating the test is a prudent step. This action is critical because the initial result may be influenced by transient conditions such as the position of the piston or the temperature of the engine at the time of testing. Repeating the test ensures that the leakage percentage is consistent and not a result of a one-time anomaly.

Leakage tests measure how well the cylinder holds pressure; a reading of 80% leakage suggests significant issues, potentially due to worn piston rings, leaking valves, or head gasket failures. Confirming this reading through a second test helps in diagnosing the engine's condition accurately before jumping to conclusions about repairs or replacements.

It's essential to establish if the high leakage result is an ongoing issue or an isolated reading, which can inform the next steps in repair or maintenance. Thus, retesting is a sound strategy for accurate troubleshooting.