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In 88F ambient temps my car got up to 248F yesterday, is anyone else experiencing temps this high? I was short shifting, mostly idle time, AC was on. I have experienced this issue twice now in heavy traffic, curious if other owners have had issues. Coolant tank is full, no leaks, fan is running.
Something's wrong somewhere... that's not normal for a C7. I realize that's not a helpful diagnosis, just didn't want you to think this was just "something you had to learn to live with".
Sorry. Not normal. I have a 2015 Z51 M7 and I am in stop a go traffic for at least 20-30 minutes every day on the way home. Last week was close to 100 degrees here. With AC on mine barely broken into the 200's. Probably not even 210.
my 17 GS ran at 210 deg. F in city traffic when the outside temperature was 123 deg. F did not overheat it does much better in the heat than my 2007 C6 ever did.
There have been a couple of these cases that were traced to a defective (not leaking) water pump. The bad news is there is a thread in the general section that these pumps are nearly impossible to get right now so hopefully that isn't the problem.
What year is your Z51? There was a report in 2014 of a few of the cars having an improperly formed opening in the overflow/degas tank so that the cap didn't seal properly. Although there was no obvious leak over time it resulted in air in the cooling system and random overheating events.
Did you have trouble with coolant temp when the car was moving at a steady speed above 35 mph? If not that might indicate an issue with your cooling fan circuit. The cooling fan should be on high speed when coolant temp is 235 degrees or higher. Do you know if it was turned on when the temp got this high? Do you know if it was running at high speed?
Bill
Last edited by Bill Dearborn; 06-29-2017 at 11:18 AM.
Did you have trouble with coolant temp when the car was moving at a steady speed above 35 mph? If not that might indicate an issue with your cooling fan circuit. The cooling fan should be on high speed when coolant temp is 235 degrees or higher. Do you know if it was turned on when the temp got this high? Do you know if it was running at high speed?
Bill
The fan was running at high speed, no issue with overheating at speed.
It sounds like you and I have the same symptoms... I got my pulley swapped 2 weeks ago and noticed my temps have since been spiking whenever I accelerate and still higher than normal when idling. Its like my radiator is not longer operating.
I have an LMR billet housed 160 thermostat and it only has around 1000 miles on it. Originally after install, car stayed very cool and actually would sit just under the optimal running temp unless I was sitting in traffic. Now, fan is running real fast as soon as the car reaches temp and will run 100% of the time after and continue running for 2-4 minutes after the car shuts off. Normal idle temp is 1-2 ticks above optimal, and when I accelerate, both water and oil temps can get quite hot. At a steady cruise though, temps sit around 1 tick above the middle line. Coolant level is fine and I checked it yesterday, can't see any leaks anywhere.
Does it sound like a broken thermostat? Or something connected incorrectly to the radiator?
It sounds like you and I have the same symptoms... I got my pulley swapped 2 weeks ago and noticed my temps have since been spiking whenever I accelerate and still higher than normal when idling. Its like my radiator is not longer operating.
I have an LMR billet housed 160 thermostat and it only has around 1000 miles on it. Originally after install, car stayed very cool and actually would sit just under the optimal running temp unless I was sitting in traffic. Now, fan is running real fast as soon as the car reaches temp and will run 100% of the time after and continue running for 2-4 minutes after the car shuts off. Normal idle temp is 1-2 ticks above optimal, and when I accelerate, both water and oil temps can get quite hot. At a steady cruise though, temps sit around 1 tick above the middle line. Coolant level is fine and I checked it yesterday, can't see any leaks anywhere.
Does it sound like a broken thermostat? Or something connected incorrectly to the radiator?
We do appear to have a similar issue but, you have more variables as a result of your mods. I find it odd that GM has made so many part number changes to the thermostat and water pump(coolant manifold), which none are available. There is a problem with something here they don't want to admit to because there are no parts to fix it. There is Z06 owner that has been waiting 1.5 months on coolant manifold. Something stinks and GM is tight lipped about it.
C7X46, do you do a lot of highway driving? Check your radiator to see if its all caked with bugs. I checked mine and it was pretty covered, sprayed it pretty good with a pressure washer. Seemed to help my temps a bit, but not fully fixed. I'm considering taking the front bumper cover off and giving it a real good spray down and clean and see if that fixes it.
I felt both sides of my rad hoses and they were both hot, so fluid is travelling through the rad at least so the thermostat doesn't seem to be broken.
This same issue happened to me but it just overheated no matter what as soon as the car turned on it kept rising in temperature until it got overly hot. Turns out the issue was just the coolant cap, replacing it fixed the issue entirely and it was covered under warranty!
06-27-2017, 03:36 PM
C7 Z51 Overheating in Traffic
Robert
. Let us know if you find out what it is! I will be calling the dealership tomorrow.
