why does my truck overheat? on 2002 Dodge Dakota

so the deal is my thermostat stuck causing the truck to overheat so i replaced it. after replacing the thermostat the truck would overheat when at idol or speeds under 40mph and the heater would go cold. i took the truck to the dodge dealer and they pressure tested for leaks and found none and burped the system. a couple of weeks later the truck started the same issues again (overheating at low rpms) the other day i got in my truck for a short trip and the truck ran just fine, i even let it idol for a while and no overheat and not cold air. so what is causing it to intermittently overheat?

by in Columbus, OH on January 24, 2013
1 answer
ANSWER by on January 24, 2013
Could be low coolant, bad radiator cap, bad thermostat, or cooling fan malfunctioning. Some thermostats have a fail open feature so when the vehicle overheats the thermostat stays open to protect the engine. Since you say it's intermittant this may not be the case.