2000 Freightliner 12.7 operating temp. Running too cold.

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Rideandrepair, Feb 10, 2021.

  1. Inderjit

    Inderjit Medium Load Member

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    Did you replace the seals when you replaced the thermostats?
     
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  3. baha

    baha Road Train Member

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    IF you go to the winter cover be sure to leave the pass. side open a bit so turbo can get some cooling air on it?
     
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  4. baha

    baha Road Train Member

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    Sorry double trouble?
     
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  5. Rideandrepair

    Rideandrepair Road Train Member

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    I had just bought 2 thermostats when engine blew. Kit came with 2 new ones. I watched them get put in. Still have 2 new ones. The old ones were from last Truck,I had just replaced them when engine blew. Got them back for spares. History repeats itself. Good to have spares. But the rubber seals dry up. Only got 28k on inframe. I want it to seal rings up good. It’s always ran cold, same with last one.but not this cold.
     
  6. Inderjit

    Inderjit Medium Load Member

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    There are seals that are inside the housing that wear out and let coolant leak past
    through the rad and over cool the engine. they are down inside the housing.
    More often than not its the seals leaking and there is not a problem with the thermostats.
     
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  7. Rideandrepair

    Rideandrepair Road Train Member

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    We replaced seals also.
     
  8. Rideandrepair

    Rideandrepair Road Train Member

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    07BE4054-2EDD-40E0-9317-A9B155358D6C.jpeg 1D9D43EB-D54E-4904-AA88-7AB56B0C8A2C.jpeg EDD4B7BE-F7D4-4169-A5FD-4B99300CC906.jpeg Ok, finally got to warm weather. It’s 48 degrees. Idling at 1000 rpm. Fan just came on just about 200, Went down immediately to 190, fan shut off, only tan about 15 seconds. Temp went down a little more, now headed back up. Seems normal. Just running cold in cold weather.At an idle, and even cooler running down the road. Runs cool enough that Cab heat is noticeably less. Last pic is with manual fan switch on, after about one minute. That seems a bit too cool.
     
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