Temp gauges flat lined
 

I purchased a 2006 4 months ago with 55K miles on it. When I was driving at highway speeds the other day, the check engine light came on and the temp gauge flat lined to zero. I/P diagnostics for engine temp showed 3 flat lines before the F for temperature. When I took it to the local dealer they said it needed a thermostat installed, of which they were more than happy to put one in "after they ordered the 'kit' for $90, and the cost installed would be $390". I told him politely to forget that thought and I would call the selling dealer to see if they would do anything (of which they were quick to say 'the warranty had expired' [3 months/3000 miles]). the next day at the same speeds, it began working as normal. It since has quit twice now and the gauges all go back to normal working condition. I'm a shade-tree mechanic from the 70's and this seems somewhat ridiculous to me. If the temp sending unit would go out, it would stay out wouldn't it? If the thermostat took a s---, wouldn't it stay in that condition as well? Has any other members had this happen?
signed,
Punkin Head-ache

Welcome, sorry that mechanical issue brought you here. But it sounds like your thermostat is stuck open. Check out this post: https://www.chevyhhr.net/forums/problems-service-repairs-42/check-engine-light-came-after-coolant-guage-stop-working-8188/

Looks like you just joined the forum, Welcome. Being a shade tree mechanic from the 60's, a Thermostat could unstick since the coolant is constantly changing from hot to cold or cold to hot but usually they will hang open.

Mine did just that after this happened to me.

After 2 or 3 days everything went back to normal. I do keep a close eye on things though.

Do you get a "normal" amount of heat from your heater when the gauges die ? If you do it is not likely to be your thermostat. Most likely electrical. You could check this with an infared thermometer. Radio Shack or Harbor Frieght. Check engine temp when gauges work and when they die. If temp is the same, not a thermo. problem.

Did first dealer check for "codes"? check eng. light should set codes.
I would stay away from ANY shop that "shots from the hip" and guesses a cause.

Good Luck.

Thank you all for the information and the welcome to the sight. I really don't want to donate nearly $400 to fix a damn thermostat, but I guess that's why we can't work on the cars anymore and they truly do get the 'big bucks'. I will pursue the thermostat change since the temps fell to 30 overnight and the the car barely got warm (showing another flat lined temp gauge). I have to believe the 'stat is locked open (thank God, I smoked a block with one locked closed before, not pretty). I look forward to continued communication with the members of this site, very helpful and informative! BTW - that's a "shade tree mechanic from the 70's" there an08HHR, I was born in 1960 and the ol' man wouldn't let me touch a wrench until I was 10, so I could work on my first car.

[QUOTE= BTW - that's a "shade tree mechanic from the 70's" there an08HHR, I was born in 1960 and the ol' man wouldn't let me touch a wrench until I was 10, so I could work on my first car.[/QUOTE]

I was referring to me when I said 'as shade tree mechanic in the 60's'. Iwas born in the mid 40's

IF you do not go to a dealer the them replacement will be far less, I despise dealer service and look forward to the expiration of the 36/36 warranty.

Sorry an08HHR, I misread the statement. Thank you for your input though.

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