2016 temp gauge not working and fans running high speed

[Jasper2307]

Hi all, long time lurker but first time posting. I have a 2016 Tahoe LTZ that has a new issue that happened tonight. The wife and I had an appt about 7 miles from our house. On the way to it everything was fine, however on the way home about halfway I heard the fans kick on. Did think anything was wrong just the fans running. Then I noticed the temp gauge hadn't move from 0 degrees. I stopped to check to see if it was actually getting hot. It was stone cold. The overflow tank was at normal level and just barely warm. We finished the ride home pulled in the driveway and I checked again, still cold! Also the fans were running full tilt engine off. I restarted it a couple of time no change. fans on and temp gauge didnt budge. As I was looking for the fan relay to pull it the fans shut off after about 10 minutes with the engine off. Also no CEL light. Any Ideas before I waste more money at the dealer? Thanks in advance!

 

[Miami-Dade]

You need a new Thermostat. Happened to me on a long trip. Took it to the Chevrolet dealer. They flushed out the radiator also as they said it overheated. Just happened to my friends 2017 Tahoe as he was on a long trip. He took his to the Chevrolet dealer.

 

[Beeker702]

In

You need a new Thermostat. Happened to me on a long trip. Took it to the Chevrolet dealer. They flushed out the radiator also as they said it overheated. Just happened to my friends 2017 Tahoe as he was on a long trip. He took his to the Chevrolet dealer.

Once you replace the thermostat your gonna need a scan tool to clear the code even tho the check engine isn’t on

 

[Jasper2307]

Thanks for the replies. It seems that this is a common problem with these 5.3s. I'll be changing it as soon as I can find a thermostat. They seem to be in rather short supply right now. Probably will change the coolant temp sensor at the same time. I'll let you know how it goes. Thank for the help!

 

[p1zaul]

https://www.napaonline.com/en/p/THMHT207518

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[Bagherra]

This exact same thing happened to me this morning.
Temp gauge went to 0 and fans kicked on. Pulled over and fans ran for about 5-10 min. Restarted, and temp came back to normal.
And no CEL...

So this is the thermostat goin bad?

Btw, this is a 2016 Denali...

 

[jimbmorris67]

Anyone know the logic in the system that when a thermostat is stuck open, the fans get kicked to full speed? The computer must know temperature didn't get to operating range quickly enough so it kicks the fans on to max cooling as a fail safe?

 

[Fless]

The logic is probably determining that there is a possibility that the coolant temp sensor is malfunctioning, so it goes to failsafe. Just a WAG on my part, but it makes sense in my small brain.

 

[TChas999]

Hi all, long time lurker but first time posting. I have a 2016 Tahoe LTZ that has a new issue that happened tonight. The wife and I had an appt about 7 miles from our house. On the way to it everything was fine, however on the way home about halfway I heard the fans kick on. Did think anything was wrong just the fans running. Then I noticed the temp gauge hadn't move from 0 degrees. I stopped to check to see if it was actually getting hot. It was stone cold. The overflow tank was at normal level and just barely warm. We finished the ride home pulled in the driveway and I checked again, still cold! Also the fans were running full tilt engine off. I restarted it a couple of time no change. fans on and temp gauge didnt budge. As I was looking for the fan relay to pull it the fans shut off after about 10 minutes with the engine off. Also no CEL light. Any Ideas before I waste more money at the dealer? Thanks in advance!

This is NOT a thermostat issue. It is the temperature sensor which is a very easy fix. Follow this link for step by step instructions. I just fixed mine with no issues, in less than an hour.

 

[Bagherra]

I just saw that vid yesterday!
Ordered sensor from Amazon and will install this weekend!

 

[JEFFC]

I bought a 16 Silverado 1500 last week with the same symptoms. Live data showed ECT at 130 degrees but that was not hot enough to move the gauge. Also had a code for below temperature threshold. Replace thermostat and problem fixed.

 

[L8T BURB]

This is NOT a thermostat issue. It is the temperature sensor which is a very easy fix. Follow this link for step by step instructions. I just fixed mine with no issues, in less than an hour.

This will 100% happen again. I was in your shoes middle of last year. Had these issues and threw on a temperature sensor and thinking how great it was that it was such a cheap and quick fix.

Issue came back about a week later. Replaced sensor 2x more, before I wised up and threw a GM thermostat on it, and it's been great for the last 6 months. Pay special attention to your temperature gauge. If it isn't sticking straight up at the 210 mark after about 10 minutes of driving, regardless of outside temperature, then you've got a faulty thermostat. It will be more prevalent during cold mornings/evenings.

Be sure to check back in and update us when this issue shows back up, not trying to be a smart @$$, but honestly just so we can spread the knowledge and experiences of those who have went through this and what the true root cause/fix is.

 

[L8T BURB]

Anyone know the logic in the system that when a thermostat is stuck open, the fans get kicked to full speed? The computer must know temperature didn't get to operating range quickly enough so it kicks the fans on to max cooling as a fail safe?

If you notice, your AC compressor also will not engage when your engine is in this "fail safe" mode. Unfortunately this thermostat failure happens to some during the warm months and because the AC compressor stops, they end up throwing unnecessary money at the AC system thinking that's the issue.

 

[Jasper2307]

Okay guys here's the update on my original post. All of the above fixes didn't work! As a hedge I replaced both the thermostat and the temp sensor. Does exactly the same thing as before. As soon as I turn it on the fans kick in high gear. Temp gauge pegged at 0. Doesn't even wait for it to come up to temp. Just immediately kicked on as soon as I pushed the button. Brand new ac Delco Temp sensor, ordered a GM thermostat won't be here until April. Put it a after market thermostat until the GM one shows up. Let it run for 15 minutes hoping it needed to get warm for the new sensor to wake up, never got up to temp. Upper radiator hose is ice cold, Heater blows warm air. After 15 minutes I could touch the shields over the exhaust manifold! Was warm but should have melted some skin! Don't know if it is a bad new sensor or something else

 

[Fless]

Did you reset the code? And what's the ECT sensor telling the scan tool it thinks the engine temp is?

 

[Jasper2307]

Sorry I should have mentioned that as in my original post there was no CEL. I don't have a scan tool so in can't check for unseen codes

 

[L8T BURB]

Sorry I should have mentioned that as in my original post there was no CEL. I don't have a scan tool so in can't check for unseen codes

The CEL will not light up, it is stored as a pending code. The code is something to the effect of "coolant temp below threshold". This code needs cleared before the systems will resume regular operation. You may be able to remove the battery terminal for 10 minutes or so to reset the pending code. You can get a pocket scanner from Harbor Freight for around $50 or so. May not be a bad investment.

For reference, I used Genuine GM thermostat and temp sensor for my repair.

 

[Jasper2307]

The CEL will not light up, it is stored as a pending code. The code is something to the effect of "coolant temp below threshold". This code needs cleared before the systems will resume regular operation. You may be able to remove the battery terminal for 10 minutes or so to reset the pending code. You can get a pocket scanner from Harbor Freight for around $50 or so. May not be a bad investment.

For reference, I used Genuine GM thermostat and temp sensor for my repair.

Ill probably try unhooking the battery in the morning and see if that works. If not Ill hit Hobo freight and get a scan tool, which I should have anyway. I did use AC Delco CTS but I had to order the GM thermostat. Nobody had any in stock. Had to use an aftermarket one temporarily until the Gm one shows up in April. If I dont use it on the Tahoe I can always use it on My Silverado if I need to. Thanks for the info.

 

[Jasper2307]

Ill probably try unhooking the battery in the morning and see if that works. If not Ill hit Hobo freight and get a scan tool, which I should have anyway. I did use AC Delco CTS but I had to order the GM thermostat. Nobody had any in stock. Had to use an aftermarket one temporarily until the Gm one shows up in April. If I dont use it on the Tahoe I can always use it on My Silverado if I need to. Thanks for the info.

Did the battery reset and all is now well in the world. Everything is working as it should. Thank fo the help!