Coolant Temp Question

[MLML]

2018 Tahoe LT -- Driving to LA today over the Grapevine. Hot day, temps outside were about 110F and grade up was about 6%. Traffic slow, about 25mph. Temp gauge ran up to about 220F. Not towing anything, just 3 people in the car with A/C on. Normal? Never noticed the temp gauge move above 210F before. Turned off the A/C and eventually reached the top, temp went back to 210F. Saw tons of overheated cars on the side of the road. Scary.

Coolant bottle shows about 1/2" under the full fill line.

 

[OR VietVet]

I would say that it was normal. Regular temp stays with lower load on engine when just cruising on highway but stands to reason would go 10 degrees more under load with a/c on while trying to accel up a grade at slower speeds reached and still in an accel mode instead of just maintaining cruise speed on a flatter surface. I don't worry until 225 degrees or higher.

When was last time any service on the cooling system? Last time the radiator and condenser were blown out? Miles on the rig?

 

[MLML]

I would say that it was normal. Regular temp stays with lower load on engine when just cruising on highway but stands to reason would go 10 degrees more under load with a/c on while trying to accel up a grade at slower speeds reached and still in an accel mode instead of just maintaining cruise speed on a flatter surface. I don't worry until 225 degrees or higher.

When was last time any service on the cooling system? Last time the radiator and condenser were blown out? Miles on the rig?

I spoke to Chevy dealership and they said that sounds normal as well. I was concerned as I've read that the temp is pegged at 210 unless there's an issue. Chevy guys said that is not the case.

Rig has 32k on it, and hasn't had a radiator flush yet.

 

[OR VietVet]

Anytime I have ever exceeded normal temp on a thermostat, even by this much, I personally flushed and replaced thermostat and installed fresh coolant. That is me though and I am very picky about my services. That thermostat spends it's whole life opening and closing, literally thousands of times and if it operates out of it's normal range, I change it, but again, that is me. In all likelihood you will be fine but I love spending other people's money $$$$$$$$.

 

[Miami-Dade]

I spoke to Chevy dealership and they said that sounds normal as well. I was concerned as I've read that the temp is pegged at 210 unless there's an issue. Chevy guys said that is not the case.

Rig has 32k on it, and hasn't had a radiator flush yet.

My temperature rarely goes above 210. In hours in traffic on I-95 in Miami,Virginia,Maryland and NYC [90 minutes just to cross the GWB or Lincoln Tunnel] my gauge will go ever so slightly higher over 210. I have never cut off the the a/c because of that. In fact the a/c has been on since I bought my Tahoe back in 2016.

I have never flushed out my coolant. Just had my Tahoe serviced [110K miles] and the dealer said the coolant is still good.

 

[Fifty]

The thermostat cracks at 194 and is fully open at 214 I think.

I believe the target temps in the ecu are in the 211 range

the new epa mandates require engines to run hotter to run “clean”... smh...

 

[bigjscfn75]

I have a 2009 Yukon xl 5.3 I just went over grapevine towing my boat which is 5000 loaded a/c off 5 passengers temp was 225 and trans temp was 230 I was in tow haul mode it makes it but would love advice on how to keep it cooler to!