Temps too hot

[Forza1088]

Hey all,
I have a 2013 Ram 1500 Longhorn and for the first time I'm having an issue. The dash started displaying "temperatures too hot". So I flipped through the screens to where all temps are displayed and sure enough temps were 230-250. Is that high? What's it supposed to be normally? I checked the coolant and it was definitely way low so I added an entire container worth which was probably just shy of a gallon. Drove it for ten minute and it didn't help. Crazy thing is that it fluctuated from 249 to 224 is like 3-10 seconds so I found that weird. Has anyone come across this and what do you think?? Thank you in advance!

 

[WilliamS]

Does it heat up when sitting or when you are cruising or both?

Could be the fan is not kicking on properly, thermostat is sticking, or the water pump is failing. If you can say it doesn't heat up when say you are driving 50mph constant, that would almost rule out the fan.

Also in 2013 the hemi is 5.7 not 5.9

 

[Forza1088]

You're right on the 5.7 thanks, small boo boo. While driving it would get hotter and would also drop out of the blue. How do I go about checking all of the items you mentioned?

 

[RysRam]

Make sure you're using the correct coolant while you're at it. 2013 and up require a specific OAT coolant.

 

[KCaudill]

OAT the Red stuff?

 

[COPPERHED DAVE]

Seems high mine gets to 203 degrees and then drops down to 199 or so when thermostat opens.

 

[WilliamS]

if it still heats up when you are cruising on the highway or long roads to overheat temps its likely not the fan. As the air pushing over the radiator would have been more than enough.

So that narrows it down to the thermostat or water pump. First fill the radiator and overflow and have keep the caps off. Obviously cold engine. Have someone else start it up and rev it to 2000-3000 you should see the water suck down a little in the radiator as its now a pressurized system. If the water doesn't move at all, sounds like the water pump is on its way out. If you see the water move, this would tell me to start at the thermostat which is a very easy fix.

This is old shade tree mechanic thinking. I cant say it will 100% work but this hasnt let me down in the last 20 years of working on old cars.

 

[ExpressRules]

If it was "way low" when you first checked you may have a leak someplace. Check the cap and you now also have air in the system when you tried to fill it back up. With it sitting at idle take a careful look for any signs of leakage. Also check the level on the overflow container and make sure you don't have white exhaust.

Not to long ago the Durango my daughter drives started to over heat on her. The coolant was low and when I brought it up to proper level let is idle for a long time and temp stayed fine. But it turned out at higher RPM the cap was leaking like crazy. Got a new cap and all was fine.