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Caterpillar 3126 after coolers

Discussion in 'Engines' started by kumu, Aug 12, 2010.

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  1. kumu, Aug 12, 2010
    #1
    kumu

    kumu New Member

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    I had my after coolers pulled and boiled out after 1,000 hours. When we picked them up to be re-installed, a large percentage of the small blades that are recessed into the housing (where the air passes through) had been folded over. Has anyone ever had this happen before? One after cooler had approx. 50% folded over and the other approx. 70%. Rather than purchasing (2) new after coolers (at about $2K a piece) I spent about 3 hours with a small pair of tweezers carefully bending the effected blades back. Has anyone ever experienced anything like this before? Potential causes that my mechanic has come up with are:
    1) radiator shop who boiled out the parts damaged the blades (this seems unlikely being that even if the part was set down on the improper side, the blades are recessed and therefore wouldn't be exposed to the surface.

    2) extreme heat in the cooling system caused the blades to soften and bend over

    thank you
  2. Marmot, Aug 12, 2010
    #2
    Marmot

    Marmot Senior Member

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    Everyone who has mishandled a heat exchanger has seen or done this. The fins get bent because the units were not properly handled. You should not have accepted them in that conditon.

    Air conditioning supply houses sell fin straighteners that look like midieval torture combs that will make short work of straightening the fins with little or no permanent damage. Your attempt to straighten them with tweezers is like painting the boat with Q-tips, it will take forever and won't do a very good job.

    It really is important to have those fins as straight as possible and spaced correctly to ensure proper airflow. You are kind of stuck now that you took the units out of the shop but I reccommend that you go buy a fin comb and finish it correctly. Almost certainly, no permanent damage has been done so far.

    I just looked at Google "fin comb" to get a link for you and found lots of references. There is even a video of how to use one and it appears that Home Depot even sells them.
  3. K1W1, Aug 12, 2010
    #3
    K1W1

    K1W1 Senior Member

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    HI,

    I don't want to bend anyones fins with this one but....

    Are you sure your cooler cores are reuseable?

    There was a lot of trouble with them when the engine series was new, I was under the impression that they had a finite life cycle.
  4. Capt J, Aug 12, 2010
    #4
    Capt J

    Capt J Senior Member

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    I agree also. Cat had major issues with the aftercoolers leaking into the engines on the 3126 series and changed to a different design. Make sure your aftercoolers are not the defective ones (maybe the metal is soft and that's why the fins are bending), check with CAT, but it would behoove you to put new ones in if yours are the defective ones and CAT may even foot the bill. Call them with your serial numbers....
  5. Marmot, Aug 12, 2010
    #5
    Marmot

    Marmot Senior Member

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    Wouldn't the shop have identified the units as failed or at risk of failure? Unless they were sent to a shade tree radiator shop behind the used tire store they do inspect the parts for servicibility and pressure test them.
  6. Capt J, Aug 12, 2010
    #6
    Capt J

    Capt J Senior Member

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    If they returned them with a bunch of bent over cooling fins, do you really think they inspected and pressure tested them? LOL I'd definately have my doubts.
  7. K1W1, Aug 12, 2010
    #7
    K1W1

    K1W1 Senior Member

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  8. kumu, Aug 12, 2010
    #8
    kumu

    kumu New Member

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    thank everyone for all the input. I think my mechanic already checked the serial numbers of my motors and they are not part of that defective batch, but I'll double check. It seems to me that for a radiator shop to bend those fins over to the extent these were, you would almost have to do it deliberately. In any event, both turbos were in need of replacement as well (one required new and one re-built) so needless to say, this has been a significant project. It all started with troubleshooting excessive black smoke (soot). Now that I'll have new turbos, cleaned air sep filters and a thoroughly reconditioned cooling system, the problem will hopefully be solved!
  9. Marmot, Aug 12, 2010
    #9
    Marmot

    Marmot Senior Member

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    Depending on the size of the shop and other internal QA controls, the bending probably happened when they were in the hands of the shipping department.

    Most shops I've worked with are very careful to place fiberboard covers over the flanges to protect the tubes and/or fins from damage and contamination.

    Sometimes bad things happen at good shops, that's why it's always a good idea to inspect the parts before taking them away if at all possible.