GM-GMC: 03 safari overheating when towing, gmc safari, radiator cap

Question
This is my first year towing a travel trailer. It only weighs 4100 pounds. Which is being towed by an 03 gmc safari awd 4.6l.

Since I've been in 100 plus degree temperatures, I can't get more than 20 miles at the most before the engine temperature begins to royally overheat. When it's near the 260 mark, I pull over and let it cool down.

This does not seem to be normal behavior to me. I've read that this may be due to a bad radiator cap? If not, what else could most likely be causing the problem?

Thanks.

Richard in steaming hot amarillo texas


Answer
Yes a rad cap could certainly cause that concern.  As could a faulty thermostat or a partially plugged radiator.  If you run into that overheat condition again you can try turning the a/c off and the heater on high, this sounds crazy but it will help to cool the engine off by removing some of the heat from the cooling system.
Hope this helps