changing thermostat 01 cat c15

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Nomad 575, Sep 18, 2011.

  1. Nomad 575

    Nomad 575 Bobtail Member

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    Sep 18, 2011
    Laytonville Ca.
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    need to change thermostat in my 01 c15 as its must be stuck open as I can't get heat in engine except when pulling a hill as it will warm up to 200 and fan comes on . my question is how hard of a job is it to change the thermostat is it a fix I can do in my shop at home.THANKS
     
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  3. AUSSIE DAVE

    AUSSIE DAVE Road Train Member

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    Feb 21, 2010
    OZ - Brisbane
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    changing thermostat should not be a problem, but Im not fimilar with the C15 setup.
     
  4. gunner76

    gunner76 Medium Load Member

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    Mar 11, 2010
    IA
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    if it's like the one in my '07 C15 acert it shouldn't be too bad. I tackled the job by myself without ever doing it before. I took my time, making sure I studied how everything was put together and it took me about three hours to do it. You need to drain the coolant down, then remove the upper radiator hose, unhook any smaller lines that go from the Tstat housing to recovery tank. then loosen up the clamps that secure the section of hose that connects the Tstat housing to the waterpump. Then remove the three bolts that hold the housing to the engine block, it will be the one in the center of the housing and the two on the lower right. You will eventually need to remove all the bolts, so if you take out the wrong ones first it's no big deal. There is also an elctrical hookup on the bottom side of the housing.

    After you get the housing off the block you need to break it into two halfs to get to the Tstats. Pull the Tstats out and then pop out the brass seals that are beneath the stats(this was the hardest to do)and be careful not to ding up the housing. Then you want to scrape off all the old gaskets and clean everything up really well.

    To reassemble, tap the new brass seals in(with the channel side pointing down)with a block or wood or a large socket that is the same diameter. Then push the Tsats in as far as they will go. They will be a little higher than the housing, but will compress the rest of the way in when you reassemble the two halves. Next take the gasket that goes between the two halves and lightly coat it with black silicon(you don't have to use silicon, but it will help things seal up better)and put the two halves together. Tighten the bolts up as tight as you feel safe doing. You will have to compress the Tstats in the rest of the way so make sure you get the bolts tight. Do the same thing when installing the gasket and bolts that hold the housing to the block.

    It's a good idea to put some antisieze on the threads and shoulders of the bolts before installing them to help prevent them from sticking. Also look the bolts over really good and if they are pitted really bad you should replace them.

    After the housing is back on the block, hook up everything you removed and refill with coolant. Take the truck out for a drive and get it warmed up enough to get the Tstats to open up and then check for any leaks. it's also a good idea to go over the bolts a couple more times to make sure they stay tight.

    Another thing, depending on the platform the engine is in, you might have to move the altenator out of the way to remove the Tstat housing. I didn't have too in my 9900ix, but your truck may be different.
     
    OmcCheese Thanks this.
  5. Nomad 575

    Nomad 575 Bobtail Member

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    Sep 18, 2011
    Laytonville Ca.
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    thank you guys, after reading your instructions............piece of cake .Thanks again and ...stay safe!!!!
     
  6. gunner76

    gunner76 Medium Load Member

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    Mar 11, 2010
    IA
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    I thought of a couple of other things to do if you haven't already tackled the job. After you remove the upper rad hose from the Tstat housing the housing will be full of coolant(about a quart & half), I take a tube style suction pump and get out all the coolant I can so it doesn't run down the side of the engine when the housing is removed. Also, now would be a good time to replace the short section of 2" diameter silicon hose connecting the Tstat housing to the waterpump.
     
  7. Kgriff1980

    Kgriff1980 Bobtail Member

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    Jan 11, 2023
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    I have an 06 Peterbuilt with a C15 Acert and it is constantly dumping coolant out of the reservoir tank. I've replaced the coolant tank cap for the 3rd time and it still has the same problem. I was wondering if the thermostats could be causing it or if it is another problem? Can you please help me find the problem?

    Thank you
    Kris G.
     
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