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Is it possible that the oil control rings might be worn to the point that you're burning significant amounts of oil, but the compression rings still be good? Or do they typically wear out together such that burning oil and low cylinder pressure go hand in hand?

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    In other words, can an engine experience high oil burn rate but still have good compression? Is this your question? – Zaid Jul 5 '15 at 9:46
  • My gut check says they should basically wear together (for the most part), but I'm not finding anything to back it up. You have a lot of other things which could happen which would damage the compression rings before the oil control rings would go bad, though. I'll keep looking for something authoritative on the subject. – Pᴀᴜʟsᴛᴇʀ2 Jul 5 '15 at 11:59
  • @Zaid Yeah, pretty much - does burning oil usually imply loss of compression. – Robert S. Barnes Jul 5 '15 at 12:38
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Rings generally wear at the same rate meaning that when it's time to replace one you should be replacing them all as they're not seating with the cylinder properly any more.

Burning oil does not always imply a loss of compression. Cars with good rings will burn oil due to bad valve guides or bad valve guide seals.

A compression test should help you isolate this issue.

  • I'm talking about significant amounts of oil. Can significant amounts of oil be burned just through valve problems? – Robert S. Barnes Jul 6 '15 at 19:35
  • Significant is kind of a subjective term, but in my experience yes they can. Losing a quart every 1000 miles or so is possible with valve guides, but it could be rings, pcv system or a combination of things. You're likely having a performance loss as well. Valve guides you'll experience just oil consumption. Rings you can have oil burning but you'll also get excessive oil fouling and the possibility of "gaining" oil as oil burns but gas will blow by and condense in the oil. This can get bad enough you might see an oil level increase. A compression test is what's needed. – elmerfud Jul 6 '15 at 20:20
  • With some engines, losing or using a quart every 1000 miles is called normal. This doesn't have anything to do with rings or valves, but with oil going out through the PCV. – Pᴀᴜʟsᴛᴇʀ2 Jul 7 '15 at 0:08

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