Coolant Temperature Sensor

Discussion in 'General Chevy & GM Tech Questions' started by Skyking75, Feb 24, 2010.

  1. Skyking75

    Skyking75 New Member

    I have a 2007 Silverado with a V6. I was on the way to work today and my temperature gauge quit working. I also got a dashboard message saying "Engine Hot A\C shutting down. The truck was running just fine. I left work at lunch and halfway to the auto parts store the guage started working and the code went away. I am thinking that the Coolant Temperature Sensor must be bad or going bad. I bought one and got home. I cannot find the sensor on the truck. I can't even find the thermostat. I was hoping somebody has a picture that shows the location of the sensor.
  2. jedepsub

    jedepsub Rockstar

    1. Drain the cooling system to a level below the ECT sensor.
    2. On 6.6L diesel engines, remove the alternator.
    3. Unplug the harness connector from the ECT sensor.
    4. Remove the ECT sensor from the engine.
    5. Installation is the reverse of removal. If reusing the old sensor, coat the threads with GM sealant 12346004 or equivalent. New sensors are already coated; additional sealant is not needed. Tighten the sensor to 15 ft. lbs. (20 Nm).
      [​IMG] ECT sensor mounting—4.3L engines
      Click to Enlarge [​IMG] ECT sensor mounting—4.8L, 5.3L, 6.0L and 6.2L engines
      Click to Enlarge
    kennythewelder likes this.
  3. Skyking75

    Skyking75 New Member

    Next Step

    Thanks so much for the info. I replaced the sensor but it is still not fixed. Where is the thermostat located? I want to change that next.
  4. snorch

    snorch New Member


    I have a 2008 GMC v6 with the same issue have you figured:confused::confused: it out yet
  5. Skyking75

    Skyking75 New Member


    I changed the thermostat and it still did not work. I then decided to disconect the battery terminal. After that it worked. Maybe it just needed reset. I think if I had done that before the thermostat that would have fixed it. I still could not get the overflow tank to pull water. I was also concerned that mixing tap water witht the dex-cool would turn it to mud. I took it to the dealer and had them do a coolant flush. Now everything is working great. I hope that helps. I did replace the temp sensor first in case I left that info out.
  6. shadow32

    shadow32 New Member

    I'm experiencing the exact same thing with my '08 Silverado 4.3L V6...even the miraculous "fixing itself on its own" part. I had it scanned at Autozone and it gave a DTC of P0128. It seems to be leaning towards the ECT sensor, but I have read also that it can mean that the coolant temperature is below regulated levels.

    The two times this has happened it was cool enough out in the morning that I had the heat on for the trip to work. It has never happened when it was 90+ out and I had the A/C running.

    ~Insert ghostly theme song here~ Strange...but true
  7. snorch

    snorch New Member

    Thanks GM

    It started out that it would stop working- temp gauge goes to 0 and A/C shut down and then it would come back on its own, now it stays at 0 and A/C off with no particular trigger to make it happen , I just reset the computer and it is good for anywhere from an hour to usually a couple of weeks. I talked to a tech who said it is a common prob and that the computer needs to be updated. This sounds like a defect to me and should be a recall but with the way things are going for Gov Motors I dont see it happening :grrrrrr: , anyway I dont have the funds to take it in and pay hour(s) to have the computer dicked with so I just wanted to let you and any one else know what I found out. Easiest way to reset on the go that I have found- motor off key at off position pop hood and disconnect the main fuse box buy pulling up the handles and the lift it up just an inch for about 10 sec lock it back down .................[​IMG]
    Last edited: Mar 5, 2011
  8. shadow32

    shadow32 New Member


    I've changed out the ECT sensor ($33 at the dealership) and that didn't solve the problem.
    I changed out the thermostat and then used the method posted by snorch to clear everything out.

    Now...the wait begins to see if this did any good.
  9. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Keep us posted, and if you dont mind me asking why didnt you bring it in and make the dealer handle it? Im a fan of the dealer paying for things that go wrong under warranty.
  10. snorch

    snorch New Member

    In my case this problem started at just over 40,000 as of now I have 70,000 on this truck. I have no mods nor have I messed with anything so to have this going on really pisses me off.

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