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  1. #1

    Default Can a decompression test do any damage ?

    Hi All.

    I am in the process of buying an older motorboat, with Perkins 6354HT engines.
    I have been advised to do an oil test and a decompression test, as part of the survey, due to insurance requests.

    The owner seems to think the decompression test could damage the engines, and I, would then be responsible for fixing the breakage ?

    If I am paying a reputable company, to do the tests for me , then if anything breaks due to the decompression test, surely the company providing the service , have to repair whatever they broke ?

    I am not a total novice, and I have so far, not heard of a decompression test, causing any damage ?

    Any help & advice, would be greatly appreciated.

    Thanks in advance.

  2. #2

    Default Re: Can a decompression test do any damage ?

    arer you talking about a compression test?
    a compression test will not damage your engine if done corectly.
    i would also look into a leakdown test

  3. #3
    Join Date
    Jun 2008
    Location
    Posts
    555

    Default Re: Can a decompression test do any damage ?

    I don't know that particular engine but a compression test usually involves removing the injectors. On most engines this is a very simple process and on some others (like some older Volvos) there is a risk of breaking some seals and hence some extra repair work. The compression test itself should never do any damage so really just a question of how easily the injectors come out. I wouldn't expect the service company to cove the costs if there are issues with removing stuck injectors etc and I doubt you would ever get that guarantee. If you do pull the injectors however and the compression's etc are good I would get the injectors serviced whilst they are out unless the current owners has had them done recently. Usually a sadly neglected part of a diesels servicing.

  4. #4

    Default Re: Can a decompression test do any damage ?

    Thanks for the prompt responses.
    Yes, that is , more or less, what I thought, no great risk of damaging anything. Guess its just an over cautious owner, or, someone who has something to hide. Obviously, the company I am employing to do the oil and decompression tests, will stop, if they come across anything faulty.
    Thus absolving themselves, & myself, from any damages.
    Cheers
    WTC

  5. #5

    Default Re: Can a decompression test do any damage ?

    Quote Originally Posted by aliboy View Post
    I don't know that particular engine but a compression test usually involves removing the injectors. On most engines this is a very simple process and on some others (like some older Volvos) there is a risk of breaking some seals and hence some extra repair work. The compression test itself should never do any damage so really just a question of how easily the injectors come out. I wouldn't expect the service company to cove the costs if there are issues with removing stuck injectors etc and I doubt you would ever get that guarantee. If you do pull the injectors however and the compression's etc are good I would get the injectors serviced whilst they are out unless the current owners has had them done recently. Usually a sadly neglected part of a diesels servicing.
    Thanks, yes I have always pulled my injectors, and had them serviced, on my transatlantic sailings, but, previously, I have never purchased a boat as old as this one, therefore, I have never had a decompression test done before.
    As said, I have never heard of a decompression test, doing any damage to an engine.
    However, since the owner of the old boat is so nervous about the decompression test, and wanting to make me liable for any damages that may occur, I needed to seek advice from more experienced people , than myself, since I, have never heard of a decompression test, causing problems.
    Thanks for all your helpfull responses.
    WTC

  6. #6
    Join Date
    Jun 2017
    Location
    Annapolis, MD
    Posts
    88

    Default Re: Can a decompression test do any damage ?

    What is a DEcompression test?
    do you mean compression test?

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