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.
Well here I am over a year later after the Cold Case install. Initially overheating was a problem but there were leaks in the cooling system, which were addressed. Still having problems with running a bit hot. Before the temp needle hits dead center, the secondary fan starts screaming. Then the temp needle goes a bit past center. No leaks and coolant level is good. The temp here today is below 70 and raining so not a hot operating environment. I'm getting ready to shut an this Cold Case and go back to the OEM radiator. It seems these aluminum radiators leak after a couple of years anyway. I went down the aluminum radiator road and the ride is over unless anybody has some good insight.