My 04 S10 Blazer has started to overheat. I have a 4.3L V6 and it is 4X4. I have already replaced the Thermostat, Radiator, and fan clutch, problem is I still overheat and i run a steady operating temp of 210. The enigine started to overheat in extreme temperatures, and after i have run the truck for a while and shut it off, then back on again the temp gauge is at about 240. Any ideas on what might be causing this problem?

 

Welcome to the forum. Maybe the water pump has lost efficiency due to internal wear or the air flow is insufficient due to a missing/broken fan shroud. It's normal for the coolant temperature to rise after the engine is shut off because it takes time for the heat buildup to dissipate. Other than the gauge readout in the I/P cluster, how are you determining the engine coolant temperature? Have you scanned the PCM to see what it sensed as the temperature?

 

I had a radiator thermometer inside the radiator to check the temp as well as watching the gauge. Another question i have is about Dexcool, is there anything compatible with dexcool? how could i tell if it meets the same specs.

 

Like I posted, coolant temperature rising after the engine is shut off is normal. I just don't know about "overheat in extreme temperatures" which may or may not be normal, depending on the ambient temperature vs. coolant temperature. Other than the water pump efficiency issue, sometimes a hose can collapse internally and restrict the flow.

As for the DEX-COOL, Texaco is the supplier to GM and the Texaco branded DEX-COOL is widely available. I personally don't trust other brands that advertise DEX-COOL compatibility.