Yesterday, when driving my 2016, I noticed that the temperature Guage never came off the peg. The ambient air was pretty cool (55) here, and my oil temperature never got over about 170 or so. When I shut the car off to see if the gauge would reset, I found that the cooling fan was running continuously, and took about 10-15 minutes to finally shut off. The engine was not hot, I checked it with a laser temp gun, and the coolant wasn’t under undue pressure. Any thought on why this would happen? I have a service appointment scheduled for Friday to see what’s up.

 

Sounds like a stuck thermostat not allowing the coolent to circulate. Happened to me and is not real uncommon.r

 

The thing is that it starts running as soon as the engine is fired up, and then if I shut it off before it can heat up, it still runs for 10-15 minutes.

 

Maybe a sensor issue. But, you might wish to disconnect the battery for a few minutes and try again. The worst is that you may need to reset the windows (as discussed in the manual); but be careful of the small ground wire some seem to break. All the best, in any event.

 

Most likely from your symptoms, the thermostat is stuck open, This causes the engine coolant to circulate through the radiator regardless of the engine temperature. You stated that it was a cool day, therefore with a stuck open thermostat the engine never fully warmed up. The computer gives the engine a specified amount of time to warm up and if it does not, it will revert to fail safe mode as it could be a bad water temperature sensor. In fail safe mode, the cooling fan runs at full speed when the engine is on and a a slower speed when the engine is switched off. It will run for some time after the engine is off. From your oil temperature, it is obvious that the engine was not overheating. Check the coolant level and if full, change the thermostat.

 

That sounds like my symptoms. I’ll make sure the tech knows to check the thermostat. It makes sense that it is in fail safe mode, since the fan starts to run wide open as soon s the engine is started. Thanks for the replies.

 

I had the same problem. Had the theromastat and temp sensor replaced. Problem solved. If you are half way mechanical should only take a half hour or so to replace the thermostat. It sits top right, passenger side, on the engine with easy access I did not due my own work this time .

 

Good luck - hope you find the source of the problem and it is a simple matter to fix.

 

My 2016 C7 has been running flawlessly since the day I bought it brand new. No issues at all, except for tire and oil changes. Such a reliable car. Last week the fan started running continuously after turning off the engine... even after the car was on for less than a minute. Not enough to overheat any sensors. For others who are troubleshooting this same issue, I took AVANTI's advice, disconnected the battery for two hours and reconnected it. The problem has not reappeared and it's been more than a week. Thanks AVANTI !!!

 

If the computer is not reading any coolant temperature from the engine, the computer worries that the engine might overheat and so it runs the fan.

 

Mine did this just this week. However, the fan only ran for about a minute after shut off. It was a warm day and I hadn't driven the car in a couple weeks. Would this be normal? Hadn't noticed this before.

 

Thermostat. Sons C7 did the same thing to us. He changed the thermostat and all was fine.

 

If the temperature gauge does not move, it is likely the temp sensor. A stuck closed thermostat would cause a true overheat condition - had that happen on another car years ago. A stuck open thermostat would still let the engine warm up, just too slowly - and the car may never get up to operating temp - the temperature gauge should still work.

Ron

 

As long as you will be working on the front of the engine, order the correct thermostat and temp sensor. Replacing both isn't that hard. Most thermostats fail open.
There are many companies trying to sell you incorrect thermostats. 2014 takes a 207* stat, later years take 195* stats.

 

Many of us with 2014s consider the 195* as an upgrade and use it with no issues. An LT1 is an LT1...

 

I wonder what the computer will do if it sees the engine running a little too cool? I had a similar issue on a C5, dealer said the ECM would keep the mixture slightly rich until fully warmed up, but my temp difference was much greater than 195 vs 207.

 

The reason there are two different thermostat temps, is because the thermostat is in a different location, on the 2014 vs 2015 and up. But does 10* engine temp really make any difference?

 

I am an HPTuners user. The stock fuel maps taper off cold start enrichment well before 180* coolant temp...it's in closed loop running off the O2 readings well before that even happens. I set all my fan switch-on temps 10* lower. I am also running the Z06 fan with higher wattage, the 2019 Z06 AT thicker radiator, as well as the GMPP aux radiator. Lots of cooling on my base for its back road beat downs. Runs like a scalded dog.

 

Yes. There is a time it needs to reach operating temp if not it "gives up" and enters failure mode. The fan pegged to 100% is failure mode.

99% of the time its a bad t-stat. The other 1% is everything else that can make it happen.