Results 1 to 5 of 5

Thread: M1079 runs hot and shuts down

  1. #1
    Private
    Join Date
    Feb 2016
    Location
    pell city, al
    Posts
    9
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Default M1079 runs hot and shuts down

    I must admit, I am not a Forum savvy kinda guy. I did not have much luck finding what I was looking for. I have a 2004 S & S M1079 (LMTV) that runs hot and shuts itself down. I replaced the coolant and when I did there were small pieces of red plastic in the coolant. About 6 pieces of all different sizes about 1/16" thick. Is there something internal (maybe a fan), that may have deteriorated? I have no idea what they were or where they came from. Any help/suggestions would be appreciated.

  2. #2
    Sergeant Major M1078MAN's Avatar
    Join Date
    Jul 2018
    Location
    SW Va, Roanoke County
    Posts
    181
    Thanks
    101
    Thanked 186 Times in 80 Posts

    Default

    Interesting. can you post a pic.

    How long have you had it, and the problem

    Has anyone worked on it recently..red plastic could be from a cap or plug..
    Retired MIL/ US DoAG CIV
    1st MV 1995 M1078 (shes home)
    --Support Equip
    ----AN/MRC-69V COMO SHELTER
    ----AX56L Acutemp Fridge Freezer
    ----Model 10000MDP-CS Ready Welder II

  3. #3
    4 Star General NDT's Avatar
    Join Date
    Dec 2008
    Location
    Camp Wood/LC, TX
    MVPA
    4954
    Posts
    7,156
    Thanks
    2,077
    Thanked 3,582 Times in 1,891 Posts

    Default

    Any chunks of plastic floating around in the cooling system will for sure end up plugging the radiator tubes, leading to overheating. Flush everything and get the radiator rodded out.

  4. The Following User Says Thank You to NDT For This Useful Post:

    Third From Texas (06-10-2019)

  5. #4
    Sergeant Major Third From Texas's Avatar
    Join Date
    Aug 2018
    Location
    Corpus Christi Texas
    Posts
    185
    Thanks
    263
    Thanked 118 Times in 68 Posts

    Default

    ^This

    Only other option is to replace the rad, which will be silly-stupid-expensive because..."surplus junk from the military is meant to be sold for silly-stupid-expensive prices" LOL

  6. #5
    Colonel
    Join Date
    Aug 2018
    Location
    Port angeles wa
    Posts
    298
    Thanks
    37
    Thanked 191 Times in 114 Posts

    Default

    Chunks are bad, wonder what they came from? I assume you got them out of the bottom of the radiator when you drained it? since flow is from top to bottom they would have had to come thru the radiator to reach the bottom of the radiator. could be from a disintegrating coolant pipe coupling, failing hose, excess gasket sealant? at any rate, if that is what came out the bottom, what is stuck on the top of the radiator that was too large to flow thru the passages? I would drain enough coolant to remove the upper radiator hose and borrow/buy a small inspection camera to put into the upper port and inspect the passages. If you find a lot more red plastic, you might be able to backflush it out of the radiator. at any rate you can get a look at he passages and decide if the radiator needs internal work. The radiator of course also needs air flow to function so those passages(and the intercooler passages in front of the radiator) must also be clear. As the engine reaches op-temp the fan should be fully engaged and pulling a lot of air thru the radiator. No flow = no transfer = overheat

    Next question I have, is do you have pump output/coolant flow? There is a line that runs to the top rear port of the coolant expansion tank from the pressure side of the thermostat housing. If you remove the pressure cap on the tank and start the truck, you should be able to hear/see fluid being pumped/sprayed into the expansion tank(from back toward pressure cap). Your heater coolant input also comes from the same point on the thermostat housing, so the heater should have hot air as the engine warms. Coolant also runs down the bypass pipe(large stainless pipe in front of air compressor) to the transmission heat exchanger. It should also get warm as engine warms. No flow = no pump = overheat...

    If you have valid/unclogged radiator passages and airflow, and you have pump output/flow, I would suspect a stuck thermostat that is keeping the flow from reaching the radiator to be cooled. It is located in the housing on the top front of the engine where the upper radiator pipe connects to the engine... Quick test is to remove it, put it in a pan of water on the stove and warm it above 210F and watch if it opens...
    Last edited by Ronmar; 06-11-2019 at 11:34.

  7. The Following 2 Users Say Thank You to Ronmar For This Useful Post:

    M1078MAN (06-11-2019), tennmogger (06-11-2019)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •