Asking for Advice Fix 273 or Replace

RichardJ916 said
Here's what I found on Yahoo.com

If compression is low in one or more cylinders, you can isolate the problem to the valves or rings by squirting a little 30 weight motor oil into the cylinder through the spark plug hole and repeating the compression test. The oil temporarily seals the rings. If the readings are higher the second time around, it means the rings and/or cylinder is worn. No change in the compression readings tells you the cylinder has a bad valve

That is correct. A compression test done without oil and with oil can help you identify which cylinder is the problem and if it is rings or valves causing the problem.

You can also isolate where is the source with a leak down tester. You pressurize each cylinder and can hear the pressure leaking through the exhaust or intake to isolate which valve(s) may be your problem.