(FIXED) Temp Issues After Changing Thermostat

[PsychedDenali]

I had just changed the thermostat on my 2016 GMC Yukon XL Denali with the 6.2. Everything went fine but now my temp reading on the dash is pegged at 210 and will not move from it. I have checked with a scan tool and the ECT temp is reading 190 degrees and everything seems to be working fine except for the temp readout on the dash. I have tried clearing codes and then disconnecting the battery but the issue persists. This issue only started today when it started reading zero because the thermostat was stuck open. Before then the temp readout on the dash would work fine. Any help is greatly appreciated.
EDIT- Everything was working as it should I just was overthinking the temp readout and it doesn't help I haven't been a mechanic in a while.

 

[OR VietVet]

Welcome to the forum, from Oregon.

2018 Suburban radiator fans

Radiator fans bearing noises

rumble.com

This link applies to what you are experiencing. The thermostat is a 207 degree thermostat, from the factory. If you put a lower temp thermostat in, that is wrong. I looked and your 2016 Yukon Denali 6.2, takes the same thermostat and CTS as the 2018 Suburban 5.3.

I just did this repair on my landlord's 2018 Suburban with a 5.3. You likely had electric fans running at high speed, too.

"Landlord called around 1 pm. Was 30 minutes out of town and his radiator fans would not shut off on his 2018 Suburban 5.3 4x4. I talked him thru the fuse box under hood and he pulled the related fuse, 40 amp. Told him to finish what he was doing and reinstall and drive here. Got here at 5 pm. I had done some you tube research and found is a very common problem. When he pulled in, the fans were roaring, roaring. I removed the negative cable at battery. CTS looked like hell when removed. His dash cluster display was at 160 degrees and turns out had been that way for a few days. I chewed him out for not telling me. The thermostat looked normal but turns out is a common problem, according to dealer parts guy. I went to dealer before he got here and got a new CTS and thermostat assembly with thermostat, housing and seal. Easy to swap it all out and reassembly. Then temp at dash climbed to normal just below 210 and great heat and fans functioned normally but start up, as they cycled with a/c on, could hear a squawk noise. Did not sound normal. He is going to Maui in 2 weeks and I can have to do the fans, oil change, clean throttle body and MAF and engine air filter and CAF and whatever else I find. has 96k miles now."

 

[OR VietVet]

I had just changed the thermostat on my 2016 GMC Yukon XL Denali with the 6.2. Everything went fine but now my temp reading on the dash is pegged at 210 and will not move from it. I have checked with a scan tool and the ECT temp is reading 190 degrees and everything seems to be working fine except for the temp readout on the dash. I have tried clearing codes and then disconnecting the battery but the issue persists. This issue only started today when it started reading zero because the thermostat was stuck open. Before then the temp readout on the dash would work fine. Any help is greatly appreciated.
EDIT- Everything was working as it should I just was overthinking the temp readout and it doesn't help I haven't been a mechanic in a while.

IMO, until you change the ECT, with Genuine GM or ACD parts and the thermostat/housing with Genuine GM or ACD parts, it is not fixed. See the info I supplied about this.

 

[slupie]

I second the temp sensor