See signature for make and model. Isc 425 cummins. Have overheating issues in stop and go traffic. Fine on the highway even pulling the trailer loaded. So I take it to the local Kenworth dealer ...
Ditto on the tip about putting the tranny in neutral when stopped for a time. I found this when waiting for an accident to clear. My radiator is pristine and have a new thermostat as well as a freshly flushed radiator.