Servicing Cummins QSC 500 8.4 after cooler, heat exchange, oil+ fuel Cooler

Discussion in 'General Discussion' started by Matt DiMauro, Apr 9, 2020.

  1. Matt DiMauro

    Matt DiMauro New Member

    Apr 21, 2019
    East Greenwich Bay, Rhode Island
    44 Sedan Bridge 2007
    Cummins QSC 500
    I’m going to be removing my heat exchangers to service them and would like to know if the cores come out the same way as they do on the aftercoolers? Also, how do you go about soaking the oil and fuel cooler in the solution? is there a core in that assembly as well, if so how do you remove it and if there is not how would you clean it. Lastly, can I pressure test the core and housing together or do I need to test the core and then install it into the housing and retest?
  2. Carpediem44DB

    Carpediem44DB Well-Known Member PLATINUM Sponsor

    Aug 18, 2015
    Sanfransico Bay area
    2006 44 DB Sedan Bridge Raymarine gs165 w Quantum HD Radar
    Achilles 350 Dink
    Nick Jackson Davit
    Cummins QSC 8.3 500 HD
    Matt, There is a core in the fuel and oil cooler but it is not removable. I found a big cork at my local ace hardware store and stood the cooler unit on its end and filled with the acid solution over night then flushed with fresh water. The heat exchanger core is removable and mine came out a lot easier than the aftercooler as there are no silicon seals going the length of the core.
    If you have or can build a fixture you can pressure test the core separate from the assembled unit.
    Have fun.
  3. JimG

    JimG Well-Known Member SILVER Sponsor

    Nov 4, 2008
    Southern WV
    2007 310 DA
    Kohler 5ECD
    Twin 350 Mags
    Raw Water Cooled

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