This can be an issue since you may only need to pull the head instead of puling the entire engine apart.
- Engine Compression Tester
- Spark Plug Removal Wrench
Example Engine Compression Tester on Amazon
BETOOLL HW0130 8pcs Petrol Engine Cylinder Compression Tester Kit Automotive Tool Gauge
- If the Compression goes up the rings are leaking.
- If the Compression stays the same the valves are leaking.
Finding out if you have bad valves or rings is the first step to fixing a compression issue.
Often, if you have bad rings the heads are redone at the same time.
Of course, this can vary and depend on the engine and scenario.
If the valves are bad doing a simple test can save a lot of time and money since it is much easier to redo the heads instead of the whole engine.
Doing a compression test is a bit old schools but does work very well.