Radiator VS Thermostat

[Calicajun]

Changed out the radiator in my 2013 Tahoe from the stock one to a radiator that allowed me to installed the engine oil cooler lines. The new radiator is an all aluminum core with aluminum side tanks for the trans and oil cooler lines. I have also installed an external trans cooler (it work great).
The two problems I am having now are; the engine temp while driving only gets up to about 170 to 180. If the Tahoe is just sitting the temp will get to 210 degrees and stay there but soon after driving the temp drops. Even towing a 6,000lbs travel trailer for 700 miles the temp rarely made it to 210. The other problem that has started is once every few days the temp gauge stays at zero and a message shows up saying "engine hot A/C turned off". Then if I disconnect the battery for a couple of minutes everything resets and the gauge starts working again and the message goes away.

I had a new factory thermostat installed with the new radiator, so I'm at a lost as to what is going on the Tahoe. The only idea I can come up with is that the thermostat doesn't close all the way allowing water to flow all the time. Are thermostats suppose to stay open a little or close off completely? Anyone have any ideas or suggestions.

Thanks,
Craig

 

[Calicajun]

Update:
I just change out the thermostat, even though the existing one looked good. The Tahoe is now running well within normal operating temperatures. At first I thought it must have been the thermostat but after test driving the Tahoe around some it dawn on me. The shop just put too much antifreeze in the radiator. Okay, so it hit me while I was washing off the driveway from all the coolant that split out while changing the thermostat. To much antifreeze will cool an engine more than it should along with other little problems.

 

[Calicajun]

Update:
Still no luck, thought the problem had been solved but no both problems are still showing up. The engine hot message still comes up every three days or so and goes away after disconnecting the battery. My son had a thought on this problem, he was wondering if the new larger radiator could have less pressure in it due to the larger volume tank and that might be causing a sensor to get a false reading. Are there any pressure sensors or any sensors that can be affected by too large radiator? Still can't figure out why the temperature gauge is reading 170 degrees while driving down the freeway. The temperature gauge does read 210, never any higher, around town. Is there any way to tell what the actual engine temperature is, as I really don't trust the in dash gauge?

Thanks,
Craig

 

[STORMIN08]

It maybe time to realize that
1. Larger surface area means better cooling
2. Aluminum disapates better

both will lead to lower temps by the gauge....I dont think you should worry about the dash gauge, look into the temo sensor or possibly a loose or damaged connection.

 

[Calicajun]

Yes, I do understand that the larger radiator will cool better but that should only happen when the thermostat opens. Until the thermostat opens it shouldn't make any difference if I have a small radiator or one the size of a house installed. At least that the way I thought it worked. I have been thinking that the larger side tank on the radiator which is all aluminum could be cooling the engine oil too much as there is no thermostat on the oil cooling lines and the old radiator had no side tank for the engine oil cooler.

Will investigate to see how many and where any or all temperature sensors are under the hood. Right now I have one sensor driver side just below the first spark plug (OK, someone told m where it was located).