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engine compression question

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  • engine compression question


    I searched but couldn't find anything this specific.

    As I understand the actual compression #s are important but more importantly is their consistency across all cylinders.

    I found a car that has a compression of

    1. 235
    2. 232
    3. 235
    4. 205

    While they all are way above the average, I am concerned about the last cylinder because it basically has a 30psi difference.

    What's you take on this. Is this gonna lead to some sort of a problem?


    BTW I do not have the leakdown numbers handy

    - Tire is the other control arm bushing.

  • #2
    Can you repeat the test? Was the battery getting weak on that last cylinder? I would bet that 99% will test the front cylinder first, since, hey, it's # 1 right? If you can repeat the test do #4 first, see if that changes anything.

    Put some oil, whatever's in the crankcase, into #4 (do a "wet" compression test. If the # comes up, that indicates that there is an issue with the rings in that cylinder. I say "issue" rather than "problem" because maybe they are stuck.

    I would follow up with a leakdown test if at all possible.

    These compression numbers don't inspire me to run like hell away from the car, but I would do some more investigating.

    Don't spend your last dime buying a car that may be needing engine work in the near future.