I have a 99 Suburban that seems to be having some issues with either the temp gauge or the cooling system. The issue is when you first start out driving the gauge will rise up to almost 240 then once you are on the highway or road it stays around 195. I have put in a radiator with in the last 5 years, I just replaced the thermostat, and also replaced the fan clutch. It currently has water in it but there some dexcool left in the overflow bottle. Any thoughts on this would be great.