Do I Have Bad Valves or Bad Piston Rings?

By | August 5, 2024

Do I Have Bad Valves or Bad Piston Rings
If you have an engine with a compression problem you need to know if it is the valves or piston rings.

This can be an issue since you may only need to pull the head instead of puling the entire engine apart.

Knowing if the rings or valves are bad will point to the fix that is needed.

There is an easy way to find out by doing a compression test.
Do I Have Bad Valves or Bad Piston Rings Compression Test
A compression test will show if the engine has lost its compression, which would mean the rings are likely bad.

If the engine holds its compression, the rings are good, and the valves are likely bad.

Doing a compression test is quick and easy to do with the right tools.

Tools Needed To Check for Bad Piston Rings

  • Engine Compression Tester
  • Spark Plug Removal Wrench

How To Do a Compression Test and Check the Rings

  • First do a Dry test and see what the pressure is.
  • Next insert roughly 10cc of engine oil into the cylinder and do another test.
  • Do I Have Bad Valves or Bad Piston Rings Compression Test Wet

  • If the Compression goes up the rings are leaking.
  • If the Compression stays the same the valves are leaking.

Summary
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 school but does work very well.

One thought on “Do I Have Bad Valves or Bad Piston Rings?

  1. Michael Yanoff

    My vehicle: Ford 2006 F150 King Ranch/Lobo 5.4 .
    Codes: PO340, 344, 345, 349
    I am in Mexico. Would love to get your advice before I take it to Mechanic here. Thanks.

    Reply

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