Temperature only High in the Road

[Ametz]

Hi Everyone !

I have a 2011 Chevrolet Tahoe but in the city the temperature always behaves perfectly, on the highway after I pass 70mph the temperature begins to rise slightly but if I turn off the AC it returns to its normal state.... I replaced the fan with a new one, I also changed the thermostat, I also changed the water pump, and finally I changed the radiator for an aluminum one for a 3-column one so that it cools the system much better. but still on the highway ONLY the temperature goes up and I have to downshift or turn off the AC to get the temperature back to the center of the gauge. Is there someone who can help me and tell me what could be happening.

 

[Foggy]

What temperatures are you actually getting ??? and what are your Trans Temps ???
This will help

 

[OR VietVet]

Some of the aftermarket radiators are suspect but maybe the small hose at the neck needs the restriction. Try a small hose clamp to partially restrict the flow and see what happens. Lots of threads about this, do a search. Air dams all in tact? Any restrictions in front of a/c condenser?

 

[Geotrash]

Hi Everyone !

I have a 2011 Chevrolet Tahoe but in the city the temperature always behaves perfectly, on the highway after I pass 70mph the temperature begins to rise slightly but if I turn off the AC it returns to its normal state.... I replaced the fan with a new one, I also changed the thermostat, I also changed the water pump, and finally I changed the radiator for an aluminum one for a 3-column one so that it cools the system much better. but still on the highway ONLY the temperature goes up and I have to downshift or turn off the AC to get the temperature back to the center of the gauge. Is there someone who can help me and tell me what could be happening.

Your coolant won’t boil until at least 260°F so slightly elevated on the gauge is of no concern.

Next steps: make sure the AC condenser is clean, replace the coolant temp sensor (cheap and easy).

Do you by chance have an aftermarket (large) transmission cooler in front of the radiator?