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Cat d9h relief valve poped off why?

Discussion in 'Dozers' started by fiat41b, Jul 8, 2019.

  1. fiat41b

    fiat41b Senior Member

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    Ok the title seems right
    we have a d9h its on a job and the relief valve for the radiator pops off
    its sat for 6mth thru the winter just dry enough now to work it where its located
    I seen this before I just let it do its thing and settle down, i only did it a couple times for me and i have put over 300 hrs on it
    I just did 37 hrs on it now i have a guy on it and he is telling me its spuing out antifreeze thru the relief
    i never have to add oil or coolant to this tractor however i did top off the radiator overfilled just before he got on it
    he is 500 miles from me i told him to see if bubbles are coming up and out he said it looks only like a little foam such as when you run you faucet in the sink
    I have a box of receipts on this tractor
    newer engine rebuild and new radiator make that a second new as 1st was damaged in land clearing stick stuck it.
    that was over 300 hrs ago.
    any suggestions oh and its not over heating and no oil in radiator or coolant in engine
     
  2. Delmer

    Delmer Senior Member

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    My 9H's are all too far away to look so I'm guessing:D

    Does this have a reservoir? or just the radiator and cap? If there's no reservoir, then the top tank of the radiator is the expansion space and you can't fill it all the way to the top, typically you want the level an inch down from the bottom of the neck.
     
  3. fiat41b

    fiat41b Senior Member

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    yea i will have a look tomorrow headed down to see it
    it has no reservoir
     
  4. John C.

    John C. Senior Member

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    Those machine have a great big radiator cap and not a small one like a car. There is a relief valve right on top of the radiator with a little hole out the side. You can take it apart and replace the parts inside. A lot of time they are just old and never had any attention.
     
  5. kshansen

    kshansen Senior Member

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    pressure valve.png pressure valve01.png
     
  6. Bls repair

    Bls repair Senior Member

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    What is engine temperature running at
     
  7. fiat41b

    fiat41b Senior Member

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    I fired it up and took it for a short test run, I have a heat gun and have shot it all around and it was 148 to 190 but mostly below
    that's shooting all the radiator, all the different temps are from top to bottom and the head - thermostat housing and the sending unit areas
    The lower engine block was 210 maybe a 214
    Here is what the gauge was reading its just a color gauge
    green upper green upper yellow then red I ran it for 45 minutes and it was reading close to the yellow we do blow the radiator out with a air compressor
    I was not running it real hard never have to as its just cutting trees with a v/sheer blade
    I parked it with it running and broke the radiator cap loose slowly as it had pressure and it sprayed out with suds-foam then I had the helper open the throttle it all lowered and was flowing but I was not getting big type pop up bubbles just high flow and foam .
    Yesterday I talked to a old mech but he does not go out and turn wrenches any more on the job but he knows these old 9's a bit
    he told me to go and warm it up with the cap off and when it foams put some of that foam on a sheet of paper to ck for oil that takes a while, I did no sign of oil
    he said it could be a number of things from the oil cooler around injectors heads and head gasket ect.
    I hate to tear it all down chasing a unknown
    yesterday while I did this I filled it just a little bit below the bottom of the neck with added water cranked it up for a good 1/2 hr low and high idle
    and got the thermo to open the temp was up in the mid green I unscrewed the cap and it had some pressure pushed some out not much and there was no foam yet and no sign of bubbles or air popping up
    however the coolant has risen to the top of the neck I shut it off as there was no more I could do it keep rising very very slow so maybe it was expanding I know thing get hotter when you turn them off.
    oh yea I opened up the crank fill and there is no sign of milky looking oil at all in or around the cap
    the engine does not smoke at all
     
    Last edited: Jul 10, 2019
  8. Vetech63

    Vetech63 Senior Member

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    The hottest point on your system will be at the thermostat housing and the inlet at the top of your radiator. You need to compare your heat gun reading with your dash gauge to have an accurate comparison. Your temp should drop 30 - 35 degrees from the top of the radiator to the inlet of the water pump on average.
     
  9. John C.

    John C. Senior Member

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    I've never seen a dozer drop that much in temperature. Usually was lucky to get twelve or fifteen degrees between thermostat housing and radiator outlet.
     
  10. catman13

    catman13 Well-Known Member

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    pull the cap off and warm it up and run it at 1/2 throttle and smell the radiator and see if it smells like exhaust,
    my d5h started running warm had some small bubbles in the radiator and it looked like it had steam coming out of it but it had a blue look to it and I smelled it and it was exhaust , had tiny crack in the head gasket , new gasket and the heating problem was fixed
     
  11. Nige

    Nige Senior Member

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    John's right. The rule of thumb for a conventional radiator like this one is around 15 degrees temperature difference between the top tank and the bottom tank if everything is in good working order.
     
  12. Mobiltech

    Mobiltech Senior Member

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    There is a chance it’s pressurizing from a compression leak but I would bet if you quit overfilling or adding coolant it will eventually find its happy place and go back to just releasing air out of the relief valve. From this point the coolant level will stop going down and as long as it’s not heating it will be fine.
     
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  13. kshansen

    kshansen Senior Member

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    I was thinking along the same lines. If filled right to the top there is no place to go but out the overflow.
     
  14. fiat41b

    fiat41b Senior Member

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    Ok but where could the suds be coming from ? I don't see constant uprising bubbles with it warmed up and idling with the cap off
    maybe i should flush it with a garden hose till I see no antifreeze then run it hard and recheck to see if I see for foamy crap after I top it off with water and power wash the radiator, as I know all that coolant ran down and the fan most likely blew it thru the radiator and its really dusty out there.
    probably get a new thermostat also
    what should the rpms be on this d9h high idle 1300?
     
  15. Bls repair

    Bls repair Senior Member

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    9BD29981-FD72-409C-AE5A-B70F52D4802C.jpeg A18275E0-71DB-4206-B98D-196EA40DCA11.jpeg You could try this
     
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  16. walkerv

    walkerv Senior Member

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    Gonna need something like strips of an old inner tube to adapt it to that big fill hole or take the pressure relief apart and check it there with new gaskets to put it back together
     
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  17. Bls repair

    Bls repair Senior Member

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    A funnel with the “tube” cut off should work
     
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  18. Mobiltech

    Mobiltech Senior Member

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    I don’t think you’ll see rising bubbles through the cap. Any air coming from the engine will come through the top rad hose.
     
  19. fiat41b

    fiat41b Senior Member

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    I guess that's why they want you to fill it up to the top of the neck as it would be the only place air could escape
    the cap is off to the side and the top hose is about in the middle right where the relief is
    I think I will try the jug of that exhaust leak fluid as pictured above
     
  20. Nige

    Nige Senior Member

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    According to the D9H O&M Manual the correct coolant level with the engine cold should be within 1/2" of the bottom of the fill tube (arrowed) that is located below the radiator cap.
    upload_2019-7-12_10-54-37.png
     
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