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 New Member

    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
  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 New Member

    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.
  11. SVW

    SVW New Member

    I have a 2008 4.3L 6 cylinder with the same problem. I started having problems at 57000 miles and have done everything everyone else has but change the DEX-Cool. Mine does it every morning at just about the same place on the highway after having been parked all night. The ambient temperature in the morning is in the mid 60's and it seems to happen just about the time the truck reaches operating at 210 F. I pull over as soon as I can and pull the battery cable and reset the fault. I then drive the truck 50 miles and restart it in the afternoon with the engine at ambient temperature in the low 90's . I never have a problem in the afternoon and may drive it well over a 100 miles at that time.
  12. shadow32

    shadow32 New Member

    Well, so far so good. Going into my 8th day and no more glitches.

    Murdog-The place that I bought the truck from was not a GM dealership. I purchased the truck "as-is". I would rather do the work myself and try to discover the root cause of the problem than to pay a mechanic some obscene amount of money and "maybe" have the problem solved.

    SVW-It is odd that this problem doesn't happen when the A/C is actually being ran, isn't it? Like yours, my truck only seemed to do this in the mornings when it was cool out.

    I'm sure that there are plenty more people that have experienced this problem that are either not members of this site or just haven't posted here. I wonder if this problem is only V-6 related or if our V-8 powered friends are experiencing this too. Perhaps GM needs to do some research into this and issue a recall to fix this aggravation.

    Just my .02
  13. murdog94

    murdog94 New Member

    Got ya and i understand the fix it yourself. I misread the LT silverado and am assuming it is a different truck that i have overlooked. Either way glad its running great!
  14. Mossive

    Mossive New Member

    this just happened to me this evening! i went a bought a new thermostat to see if thats the issue but i think im going to try and pull the fuses first. If that doesnt work should i drain the coolant out of the radiator before changing the thermostat?
  15. Mossive

    Mossive New Member

    alright i switched out the thermostat (without draining the coolant, wont do that again) and disconnected the battery for a bit. now the temp guage is functioning but the needle goes straight up to the 210 degree mark and stops. is it because the Failsafe thermostat is for 195? should i be concerned?
  16. jreagan

    jreagan New Member

    Mossive, you didn't say the year/model of you have. If you've replaced the termostat, my next step is to check out the sensor and its connections (they can get corroded). And don't forget that the stepper motor might just be bad in the dash cluster.
  17. Mossive

    Mossive New Member

    oh sorry its an 08 4.3l v6 WT
  18. Chi-Town

    Chi-Town New Member

    I have a 2000 4.3L Silverado with 137,850 miles this morning my truck just shuttered and stopped . Glad to find this site and relief to read that the Temp Sensor might be my problem. Before I try Snorch's advice on resetting the board. Could resetting the board get me running again, Autozone is 4 miles away. Damn GM pump sensor failed, piston slap now this problem. What's next? Oh yeah lumbar bag went out on drivers seat. Don't get me wrong I like Chevy but now my wives 2005 Uplander is experiencing problems with right wheel hub.
    I appreciate your advice and help in this matter.
  19. jrb_fishy

    jrb_fishy New Member

    i have another thread on here major issues with 1998 chev blazer 4.3 v6 i am having somewhat the same problem my temp gauge runs all the way to red line and the coolant itself boils in the res but i have had it do this with the needle at red and the rad hose and block were both cold the only code i have is a p0300 general misfire code there is a problem with the emissions system no catalytic converter i have had the coolant flushed i have put in a new water pump and 2 new thermostats there is no coolant in my oil or white smoke from my exhaust i am starting to get really frustrated with this damn thing
  20. Fozzy

    Fozzy New Member

    I had this VERY thing happen today. Driving down the interstate.. glanced at the message about the hot engine / AC inop message and about crapped.. Pulled over, looked it over, no leaks no smells, nothing. I restarted the truck and nothing changed, drove it most of the day.. no change.. As I was headed home glanced at the temp gauge and it was right where it should be an the AC would come on.. I don't like the sounds of this! :money:

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