Engine overheating when driving?

Tiny
GCT1212
  • MEMBER
  • 2018 RAM 3500
  • 6.7L
  • 6 CYL
  • TURBO
  • 4WD
  • AUTOMATIC
  • 70,000 MILES
The engine is overheating when speeding up sits fine at idle and when cruise is set and on flat terrain the temperature holds steady but is still running hot. Had thermostat replaced in January and again in May. Also, in may had radiator flushed out and new coolant put in. Truck has been fine since then but about a week ago it started overheating again. Not sure what to do.
Friday, July 15th, 2022 AT 3:52 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,773 POSTS
When the engine is running hot or overheating can you hear the cutch fan kick in? If not the first thing was needed to do is check fuse # 78 10-amp int he under hood fuse panel, this fuse controls the radiator electronic clutch fan, if that's okay the truck may need the electro fan clutch replaced, here are the instructions in the diagrams below plus a generic guide on what to look for when the truck is overheating.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/engine-overheating-or-running-hot

I have also included the cooling fan wiring diagrams so you can see how the system works. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Saturday, July 16th, 2022 AT 6:08 PM
Tiny
GCT1212
  • MEMBER
  • 2 POSTS
Yes, the fan clutch kicks in and is working properly. Also not losing any fluid. No leaks in the system anywhere.
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Saturday, July 16th, 2022 AT 7:03 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,773 POSTS
That's good, I would use a garden hose and using the pressure setting and reverse hose out the radiator fins (fan side) and clean the front and make sure there is no hair/bugs/leaves etc. When you had the thermostat replaced was it an OEM unit?
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Sunday, July 17th, 2022 AT 10:53 AM

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