yup, having an issue with my cooling system thermostat has been replaced. The blazer (2005, 4.3l) was running fine then recently began overheating and blowing cold air. It's been run at about 110-115 Celsius, 15 degree about operating temp. A few times 120 and presumably higher and had to turn the truck off. The thermostat is not opening until it reaches the high temps even the new one, once it does then the hot air will return. I checked for leaks which there is none, including water pump. *The coolant is in desperate need of a flush* which is on my todo list tomorrow. When the engine is at operating temp while driving; it will increase in temp at an idle so possibly water pump. I was considering the rad cap if its stuck and won't open on vacuum? Have I missed something or overlooked something? Any incite is appreciated.


*I recently bought the vehicle and it was highly neglected for maintenance prior to me owning it, today I noticed signs of the engine being rebuilt, ironically has an oil leak.