hangslo
+1y
If its a 97, then it should be green. The orange coolant only came into use once GM started using iron blocks and aluminum heads. The orange helps to prevent electrolysis due to dissimilar metals.
There is nothing wrong with running a 50/50 mix, but the mix should be tailored to your specific conditions. If you have a real concern with cold temps and your block freezing and cracking, then that mix is fine ... but if max cooling is your objective and freezing is not a real problem (like here in FL), then you would be much betterr off running a 75/25 or 80/20 mix of water/anitfreeze since water is a much better coolant than antifreeze. You can even go as low as 10% antifreeze and still retain most of its corrosion protection properties with a slight increase in boiling point. There is also another product called "water wetter" that you can get at most parts stores that can decrease your temps by 5 - 10 degrees. Increasing your water to antifreeze ratio can account for up to a 20 degree reduction in coolant temp.
I also agree with the others that it sounds like a flow issue as well. Generally if you get increased temps on the road, it generally points to poor coolant flow (t-stat, plugged radiator, collapsed radiator hose, water pump going out) and the higher engine temps/speeds overload the cooling system that isnt taxed as much while driving around town. Increased temps can be caused by tranny fluid, but you should have dedicated oil and tranny coolers on your truck in addition to running thru the radiator, and if it locks up in OD then your fluid should stay nice and cool. All that said, no amount of flow will help as much as increasing the amount of water in the system. You even said it ran cooler before you put the extra antifreeze in it.
Also, 210 is not really that hot at all. My 2006 TBSS runs at 210 all day long as set up by GM for emissions. Remember, all the laws of physics (boiling point) go out the window in a cooling system under pressure. The added pressure raises the boiling point much higher ... this is why you never take the cap off of a hot radiator ... as soon as the pressure is released, it could flash boil and that just dont make for a good day!