6NZ running. Cool

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Loaderlou, Oct 28, 2020.

  1. Loaderlou

    Loaderlou Light Load Member

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    Feb 24, 2014
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    Hello friends. I have a 6NZ Cat that’s runs about 130 degrees while empty. In traffic or while loaded it may go up a bit. I’ve changed my thermostats, all my fluids are fine. No water in oil or visa versa and the engine still runs strong. I also changed my oil cooler about 6 months ago. I installed cat 195 thermos. What else should I look at, any ideas?
     
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  3. bad-luck

    bad-luck Road Train Member

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    Baltimore, Maryland
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    What type of temp gauge does your truck have? The coolant temp sensor may not be reading correctly. Use a temp gun to check it
     
    A5¢ and lester Thank this.
  4. pushbroom

    pushbroom Road Train Member

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    Change the thermostat seals as well?
     
  5. Trippin7cattle

    Trippin7cattle Bobtail Member

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    Oct 29, 2020
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    I have an 03 cat 6 NZ , I had Thermostats replaced 190. In winter it runs 186 sometimes lower. Not much though , had seals and housing replaced as well, I have to run a winter front almost closed up in winter to keep it above 175, not good to run it lower , I replaced my temp gauge with an digital one and it gives me a more accurate reading. Found out the other one was way off. The new one is easy to install. I like the digital one much better
    Try that next if you've done the rest.
    I've have my Pete 6NZ now for 6 years. Had a platinum kit put in a year ago.
    Replaced the radiator and condenser too ,
    I've just about replaced everything to do with the engine and all components from the cab to the radiator. I have a guy in iowa that only touches my engine after 2 failed rebuilds within 2 years apart , he got it right when I took it to him. So now I've got around 60 thousand I've dumped into my engine , first guy didn't do it right. My new guy knows his ####.
    He only works on one at a time. But he's good. need info send me a text 806-477-8755
    20 + years working on cat. He's certified to. And does his own thing.
     
    ANDREWS_METHOD Thanks this.
  6. Loaderlou

    Loaderlou Light Load Member

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    Feb 24, 2014
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    So far I’ve done a new radiator, new fan clutch, new fan, thermos with gaskets and seals. It’s been running like this for quite some time. The thing that concerns me the most is that my oil temp and tranny temp are in line with the thermostats.
     
    Last edited: Oct 29, 2020
  7. spsauerland

    spsauerland Road Train Member

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    West Harrison, In
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    Best to have someone hook up to it and see if coolant temp that cat engine coolant sensor is same as gauge.
     
    A5¢, Goodysnap and lester Thank this.
  8. Loaderlou

    Loaderlou Light Load Member

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    Feb 24, 2014
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    Thanks SP. I never changed the sensor. But why would my oil temp and tranny temp coinside with my water temp. For instance. If my water is at 150, so are my oil and tranny. When my water rises to 200 when I’m pulling a hill or shifting a lot, my other temps follow pretty closely. Running empty Long Island to Pa 135 degrees at best
     
  9. spsauerland

    spsauerland Road Train Member

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    May 31, 2010
    West Harrison, In
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    You probably have an air cooled transmission cooler. Oil temp is probably temp sensor in bottom of oil pan. I have noticed on many older Pete's previous of multiplexed dashes that the temp on coolant gauge is a lot of times lower than actual coolant temp and oil pressure is usually off also. Do have an IR heat gun? Have you felt upper radiator pipe after getting a load on the engine?
     
  10. lester

    lester Road Train Member

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    NW, Iowa
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    Get yourself an IR thermometer and know for sure. They are super handy to have. By your oil and transmission following temp id guess your thermostats aren't working properly. Could be bad even if new or housing is eroded and seals are leaking. Get that IR thermometer
     
    I glide 47 Thanks this.
  11. Loaderlou

    Loaderlou Light Load Member

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    Feb 24, 2014
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    Ok guys, I did an IR test on my vitals and everything pretty much matches my gauges within a few degrees. The parts guy at my peterbilt dealership says that sometimes when the water pump gets old the fins may break or the impeller shaft may start to slip. Any thoughts on that? Thanks
     
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