Matt D
Junior Member
I own a 2018 RAM 1500 Big Horn 5.7 Hemi with just over 40k miles. Recently I got an engine overheating message and saw that the engine coolant temp had risen to over 250 degrees. After 2 or 3 seconds it began to drop back down to normal operating temps, 200 - 210, and ran there for several minutes. I started watching the temp closely and after several minutes of normal city driving, it started to rise again. In a matter of 5 seconds, then temp ran up to 250, engine overheating message, then 2 seconds later cooled back down. It did this several times. I replaced the thermostat, filled the coolant and it seemed to run fine for a few days. Then yesterday the temp jumped up again, engine overheating message, temp goes back down. Any ideas??? I'm thinking maybe a sensor going bad? I can't imagine engine coolant changing temp that quickly.