I've added a bunch of weight with all the skid plates you can put on an X. Now put in some gear in the back, load up the family and hit the Rocky Mtns. If I run the A/C under these conditions, the temp guage will rise most of the way when I'm climbing a hill at highway speed. I have to shut of the A/C to bring the temp. back down. Somebody told me to change the thermostat to a higher temp. This makes no sense to me. I think the OEM stat is 180 degrees. My local auto parts joint sells 170 or 180 degrees. Seems to me though that it wouldn't matter which one I ran, 10 degrees isn't going to matter under these conditions. The stat is going to be wide open at this point no matter which I ran. Right? BTW. I've always maintained my cooling system very well.

I think I need to add a scoop on the hood to draw in some more cooler air, or soemthing else?

Thanks

check the fan clutch and make sure you have good air flow thru the radiator

First and easiest thing to do is to replace the radiator cap. If it isn't maintaining proper pressure it will cause overheating...

I'll get a new cap this week. I got one of those Prestone caps and I should of got it at the dealer instead. I do have a aftermarket transmission cooler mounted on and in front of my radiator. I wonder if that is causing just enough air flow restriction to cause it to run hotter under a good load?

Shouldn't...

I will say this. I bought a bottle of the Royal Purple / Purple Ice Coolant Additive. I hooked up my scanner and went on a 15 min. drive using the live monitoring menu and recorded the highest coolant temp reading. Removed just the same amount of antifreeze(with the wife's turkey baster) as what is contained in the Royal Purple bottle. Went back out for 15 minutes and the temp. never got within 7-8 degrees of the first reading. The ambient outside temp. was the same each time. 33 degrees. I can't believe a product actuallly did what it claimed. They say 8-10 degree drop in a 50/50 antifreeze mix. I guess every bit of temp. reduction I gain is a plus. I might also need to install a auxiallry fan. I'm just not sure if there is the room for one.

I will say this. I bought a bottle of the Royal Purple / Purple Ice Coolant Additive. I hooked up my scanner and went on a 15 min. drive using the live monitoring menu and recorded the highest coolant temp reading. Removed just the same amount of antifreeze(with the wife's turkey baster) as what is contained in the Royal Purple bottle. Went back out for 15 minutes and the temp. never got within 7-8 degrees of the first reading. The ambient outside temp. was the same each time. 33 degrees. I can't believe a product actuallly did what it claimed. They say 8-10 degree drop in a 50/50 antifreeze mix. I guess every bit of temp. reduction I gain is a plus. I might also need to install a auxiallry fan. I'm just not sure if there is the room for one.
I big modification on these trucks, is to ditch the clutch fan setup, and get two good electric fans, attached to a temperature sensor. Two 2400 CFM fans, will push a lot more air than your clutch fan, at any temp you decide on.

Also, I doubt your tranny cooler is causing air flow issues, as this is also a very popular mod.

Some other things I would look into, is how long has your coolant been in there? Maybe it is time for a good cooling system flush, flushing the radiator as well.