Just a follow up on my running hot situation. Pressure tested it and found a leak in the heater hose. Almost 200k so sure, replaced both. Still running hot. Pulled out the restrictor since it had no effect. Replaced the thermostat and coolant reservoir cap. I noticed that when the engine was hot and I unscrewed the reservoir cap that coolant shot out the bottom. Turns out the reservoir tank had a crack in the bottom. Replaced it and now operating at normal temp and the secondary fan never comes on, gauge is back in the middle where it should be. So if you have higher mileage on your Tahoe, leaks will likely occur when the cooling system is brought back to full pressure with a new radiator and water pump. Now hopefully this Cold case will give me 100k.