Heads-Up …Cummins After-Cooler Maintenance

Discussion in 'Diesel Engines/Drives/Transmissions/Props' started by fwebster, Jan 27, 2022.

  1. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    I am in Panama City Beach for a few days and stopped by to visit my friends in the Service Department at the marina we were in for 30 years. It is like someone dropped a bomb on Cummins owners. A late model 42 DB with 6CTA's is waiting on complete new after cooler assemblies, a newish 44DB with QSC's had an after-cooler core fail and ingested sea water thru the intake, an older 40DA had the same issue, The 44 DB owner is a new owner and decided to just replace both engines, and a 45EB just replaced his 6CTA's with New QSC's.

    All of the above were caused by a lack of regular after-cooler maintenance………..a pilot who has always done his own maintenance had a schedule change and wasn't using his boat; a 83 year old suffering from arthritis can't get in to the bilge any more; a family owned boat that the brother, son, nephew and owner fund the time to go fishing, but never thought about his cooling system maintenance, and an owner who refused to pay the marina for his maintenance got tied up in rebuilding after a recent storm.

    Life happens, but diesel engines will not tolerate seawater from an after-cooler leak in the intake air. I understand it is hard and heavy work and if you aren't able to do it or just don't want to pay a qualified mechanic top do it, please don't let your after-cooler maintenance slide because "They run fine", but one day they won't and you won't like the outcome. And for those of you who just don't use the boat much anymore, a few sunset cruises and sitting at the dock doesn't change the fact that seawater corrosion of the after-cooler continues while you watch soap operas or Ellen in the afternoon or do your day job.

    Delivery on Cummins after-coolers is 4-6 months, but new QSC's can arrive in 2-3 weeks if you decide to repower and can write the $120,000 check for the new engines plus cover the yard and mechanics bill for the labor.


    Frank
     
    Mark.60, Woody, Jaws and 10 others like this.
  2. tc410

    tc410 Well-Known Member PLATINUM Sponsor

    Oct 9, 2006
    Charlevoix, MI/Jupiter, FL
    2005 550DB
    MAN CRM-900
    Great post @fwebster (as always). I don’t have Cummins anymore, but regardless of engine manufacturer, always a good reminder to look beyond basic oil and filter routines.
     
    Mark.60, sbw1 and mrsrobinson like this.
  3. SeaNile

    SeaNile Well-Known Member

    Aug 16, 2010
    Chadds Ford, PA
    2003 50 Sundancer
    Cummins QSM11
    “Go broke trying to save money”
     
    tc410 likes this.
  4. carterchapman

    carterchapman Well-Known Member TECHNICAL Contributor SILVER Sponsor

    Mar 25, 2008
    Lake Chickamauga/Marietta, GA/Ft. Myers, FL
    2006 Sea Ray 58 DB
    MAN CRM V8-900s, Twin Disc Drives; Onan 21.5 Generator
    $120K check makes my $22K bill every four years for HE and Charge air cooler cleaning look cheap. thanks Frank.
     
    Brett H, Mark.60 and tc410 like this.
  5. bbwhitejr

    bbwhitejr Well-Known Member SILVER Sponsor

    Apr 14, 2013
    Lake Lanier GA
    2003 420DA, 6CTAs
    NA
    That is the first thing I did on both boats with Cummins engines because of the education Mr. Webster gave me. Thanks Frank!

    Bennett
     
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  6. tc410

    tc410 Well-Known Member PLATINUM Sponsor

    Oct 9, 2006
    Charlevoix, MI/Jupiter, FL
    2005 550DB
    MAN CRM-900
    I think you mean “Dr.” Webster!!
     
  7. carterchapman

    carterchapman Well-Known Member TECHNICAL Contributor SILVER Sponsor

    Mar 25, 2008
    Lake Chickamauga/Marietta, GA/Ft. Myers, FL
    2006 Sea Ray 58 DB
    MAN CRM V8-900s, Twin Disc Drives; Onan 21.5 Generator
    Doctor, Dentist, Chiropractor...he fills them all!
     
    tc410 likes this.
  8. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    Back Cove 37
    AB Ventus 9VL
    Cummins QSC 8.3 600
    Something that can really help with the longevity of the aftercoolers is installing (and using!) a freshwater flush system. Flush after every outing to prevent salty seawater from eating the system while the boat sits at the dock.

    It can be flushing caps on the strainer tops, or a fully plumbed system where you attach a hose from the cockpit. Whatever will let you flush regularly. I did this on my QSC and generator; it really seems to help.
     
  9. Mark.60

    Mark.60 Well-Known Member GOLD Sponsor

    473
    Sep 6, 2020
    Westbrook Connecticut
    2007 44 sedan bridge
    Cummins qsc 500
    Thanks Frank
    After purchasing my boat two year's ago the first thing I did was complete cooling system. That was after reading one of your posts about after coolers and proper maintenance.
     
  10. Carpediem44DB

    Carpediem44DB Well-Known Member GOLD Sponsor

    Aug 18, 2015
    Sanfransico Bay area
    2000 Carver 506
    2006 44 DB Sedan Bridge
    Volvo TAMD 74 P
    I hear of folks doing the freshwater flush, but I slept better at night after installing my Salt Neutralizer injection system. I would think it would be more popular a mod as I have not ever heard that the neutralizers are ineffective. Having done the work myself and assisting on a few others, regularly servicing the aftercooler and heat exchangers does not really take too much technical prowess. Youthful dexterity does help but most of the marine mechanics I know don't necessarily posses that trait.
    CD
     
  11. Thornton69

    Thornton69 Well-Known Member

    916
    Sep 15, 2014
    Northern BC
    1981 245 SDC
    2021 Solar 420
    '97 5.7 Bravo 2
    '20 Merc 25 EFI Jet
    Like everyone else, Cummins seems to have long wait periods for a lot of their components in Canada as well. Especially the older cta goodies. Seems to be the way it is these days.
    Have a qsl and cta (non marine) in the shop atm. It was 8 weeks for the qsl @ 40k and having problems even getting a date for some of the cta components. Was lucky enough to have a core in the back to rob a block and crank out of for the cta.
    IMG_5002.JPG ODXG0235.JPG
     
  12. Shaps

    Shaps Well-Known Member PLATINUM Sponsor

    Nov 4, 2019
    Long Island,NY
    2010 Sundancer 500
    2015 Brig Falcon 330T
    Twin Cummins QSC550 DTS w Zeus
    When I bought my boat I had both aftercoolers replaced. I read up a fair amount on having the mating surfaces where dissimilar metals of the aftercooler meet coated with alco-metalube and made sure the new units had that.

    Has anyone else done this? What about when you service the aftercoolers? Do you coat them prior to re-assembly?
     
  13. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    QSB and QSC

    There are two factors on the corrosion issue. One is the raw water side of the QSB and QSC aftercoolers as this video shows how to properly avoid. The second issue is condensation on the air side. If you boat in a saltwater environment the intake air is laden with moisture and salt. That moisture is captured as condensate on the cold aftercooler coil then drips down onto the aluminum housing and corrosion proceeds where the water collects. For boats that idle around extensively this is a problem. Conversely, boats that are working the engines and up on boost the air is hot heats up the aftercooler housing preventing accumulation of the moisture and avoids corrosion.
    The QSM engines do not have any aluminum exposed to raw water so corrosion on the raw water side is rare; there would have to be a leaking O-ring seal. However, the aftercooler housing on the QSM's are subject to corrosion on the air side; probably more significantly than the QSB or QSC engines. Fortunately, there is a plug that can be removed at the bottom of the QSM aftercoolers to see if there is any moisture collecting and it's easy to get to.
    The bottom line is to run these engines up on boost and keep the aftercooler housing hot.
    Tom
     
    Shaps likes this.
  14. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    Back Cove 37
    AB Ventus 9VL
    Cummins QSC 8.3 600
    The video Tom posted shows perfectly how to grease the aftercooler when reassembling. Do this any time the aftercoolers are re-assembled. I've done this with mine.

    Apparently Cummins used to assemble the aftercoolers dry, but are now using Alco Metal-lube during factory assembly. I confirmed this was the case with my 2019 QSC engine. My 2018 QSB was dry when I disassembled for service.
     
  15. Shaps

    Shaps Well-Known Member PLATINUM Sponsor

    Nov 4, 2019
    Long Island,NY
    2010 Sundancer 500
    2015 Brig Falcon 330T
    Twin Cummins QSC550 DTS w Zeus
    Agreed @b_arrington
    the new aftercoolers were shipped with the metalube
     
  16. my3sons

    my3sons Well-Known Member GOLD Sponsor

    Feb 24, 2009
    NY (Lake Erie)
    2004 400DB, Onan 9 kw Gen, Highfield RIB,
    Cummins 6CTA M-3
    That is an excellent video that Tom posted from SeaBoard. It shows the placement of the o-rings well and it's easy to see how it is supposed to work. If your engines are Cummins B's and C's and you are a little unsure of what is going on with these aftercoolers, watch it a few times and pay particular attention to a few items.
    Sea water does not come in contact with the aluminum of the aftercoolers by design.
    at 1:35 in the video, note the o-ring and where it rides. Tight around the core and against the case. At 6:45, note the machining of the cap. There is a beveled edge around the inside. When the cap is tightened down during assembly, that beveled edge is what compresses against the o-ring, creating a seal against the core and a seal against the case. The seal against the core and case prevents any seawater from touching the case and any charge air from leaking out of the air side of the aftercooler. It is those seals that make us happy boaters or not. Study the video so you know where to look for corrosion or surface irregularity issues that could hinder a good seal.
    Corrosion an inch inside the case doesn't matter, it's where you see the o-ring that does.
    As he said, the problems start when there is condensate that gets between the core and the case on the charge air side of the o-rings. As said above without the protection of the grease, corrosion starts from the mere contact of the core with the aluminum case. Add the condensate and it gets worse, add a saltwater environment, and it gets worse yet. The corrosion will work its way toward the o-ring, eating the aluminum case until it chews up the sealing surface of the case where the o-ring rides. The support for the o-ring is now gone at the spot where that occurs and there is no longer any compression on that tiny section of the o-ring and a leak starts. Raw cooling water now comes in contact with the case, enters the air side of the aftercooler and things get worse from there, sea water is ingested into the combustion chambers.
    Reassembly to help ward off corrosion of these is really all about the grease as stated above and you can see in the video. Don't skimp on it. It should be oozing out when you're done, just like the video. That will help keep the end surfaces of the case corrosion free from just being in a damp salty marine environment or if a little leak develops from an anode plug until you can get it stopped.
     
    ttmott likes this.
  17. saopm

    saopm Active Member

    805
    Oct 6, 2010
    North Fork - Long Island, NY
    2005 420 Sedan Bridge
    Cummins 450
    Did mine after haul out…..Just need spring to come.

    [​IMG]
     
    Blueone likes this.
  18. Spark600

    Spark600 Active Member GOLD Sponsor

    382
    Dec 28, 2013
    South Shore Long Island NY
    2015 Sundancer 410
    Onan Generator
    Mercury dinghy
    Cummins QSB HO 380 HP
    Zeus Pods
    This will be the first season with this boat so I will be changing them over the winter
    Just got done painting them will be installing them in a couple weeks 16433874048157630207468162243496.jpg
     
    Shaps likes this.
  19. Mark.60

    Mark.60 Well-Known Member GOLD Sponsor

    473
    Sep 6, 2020
    Westbrook Connecticut
    2007 44 sedan bridge
    Cummins qsc 500
    I replaced mine last winter and I bought them from Seaboard Marine. They were greased the proper way.
     
  20. Carpediem44DB

    Carpediem44DB Well-Known Member GOLD Sponsor

    Aug 18, 2015
    Sanfransico Bay area
    2000 Carver 506
    2006 44 DB Sedan Bridge
    Volvo TAMD 74 P
    When I did mine I had some corrosion in the area where the square silicone seals contacted the aluminum case. I ground out the corrosion and used some metal epoxy patch to fill the area. I had slight pitting in the seal area but it cleaned up with some light sanding. Per SB MArines's advice I left out the square silicone seals and reassembled with a liberal amount of metal lube. I am sure mine had never been done since new. A 2006 boat with 350 hours and I did them spring of 2020.
    CD
     

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