2002 Dodge Ram 1500 3.7v6 idles cool drives hot
Asked by Guru9ZKQK2 Dec 12, 2020 at 04:45 PM about the 2002 Dodge RAM 1500 ST RWD
Question type: Maintenance & Repair
Ok guys, I have a 2002 Ram 1500 it had a radiator
leak, I replaced radiator and the thermostat and
filled the with coolant let idle with cap off for a little
over a hour. Went to leave for work everything was
fine until i got on the freeway. Started running hot
not overheating but hot. I love burped the system
multiple times and at a loss. The truck will sit there
and idle at normal operating temps all day until you
drive it
5 Answers
Sounds like there could be some air in the system. Idling doesn't open the thermostat and when it opened it allowed air to circulate and cause it to overheat or run hot. Some systems take awhile to bleed out. It's best to top off and check to see what your level is at cold. Also defective caps make it run hotter but I hope you got one with changing the radiator and thermostat.
Running hot or overheating at expressway speeds is caused by poor coolant circulation. I'd suspect a failing water pump, sticking thermostat, or clogged cooling system passages that need a good flushing out. Hope that helps! Jim
Guru9ZKQK2 answered 4 years ago
So I decided to freeze my butt off in the driveway today, 30° here in Michigan. Drain the coolant and because the aftermarket radiator I bought doesn’t have a drain plug I had to remove the lower hose off the radiator. The easiest way to do that is to take the two bolts out of the thermostat housing. As soon as it’s done draining I pull the hose back with the thermostat housing attached and right away notice the thermostat was in backwards. I’m stupid
It happens. Live and learn.
We all make mistakes! The important thing is you discovered it before any damage was done to the engine! Thanks for letting us know! Glad you fixed it! Jim
