2006 Dodge Magnum coolant temperature

KK13

MEMBER
2006 DODGE MAGNUM
5.7L
V8
RWD
AUTOMATIC
135,000 MILES

I'm having a cooling system issue and I know the problem, the question I have is this, my car has two, factory coolant temperature gauges, one is an analog (I guess) needle gauge which reads C and H with normal running temperatthy. In the middle. I assume the value to be 120°f minimum and Max at 300° with center being normal operating temperature at 220°f. Then the digital LCD temperature display. I also have an OBD2 reader and a phone app called Torque which receives and displays all readouts from the cars computer etc. With the coolant temp gauge on it. All three working simultaneously give me 3 completely different temperatures each one about 12 - 15 degrees from each other the digital factory may read 206 and the factory needle will be in the middle or a little over, and the OBD2 will read 243 degrees. Now which do I trust to be the most accurate? I need to know because besides the obvious overheating problem, the car has aluminum heads and I can't be overheating those at all for obvious reasons. This is potentially catastrophic to my beautiful fast Hemi motor. So I ask again which gauge do I believe?

3 Replies

KNOWLEDGE IS POWER

MECHANIC
1,136 POSTS

If you having an overheating problem, then I'd trust the OBD reader first.

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Sunday, March 16th, 2014 AT 7:18 AM

KK13

MEMBER
2 POSTS

Let me rephrase that question so that you may answer the question that I'm trying to ask.
I was having a problem with my electric radiator fans and my car never actually overheated. It never boiled over, never blew a hose. But as I was driving on the freeway the temperature gauge(the analog needle, factory gauge) started reading hot(a little over center mark and moving hotter) so I turned on the factory digital LCD temp gauge and it was reading 221°f which is fine and then the needle went almost to the red zone before I could pull off the road. The digital went to 230°f but the car wasnt over heating so I let it cool down and continued driving with the OBD2 reader on also. It (OBD2) started to read almost 250°f but the needle was barely over center and the digital factory was reading 218°f and again no boil over no coolant blowing into or being sucked out of the overflow tank.
So, now, which gauge do I believe. Granted the motor was hot but I live in Los Angeles and it was about 77°f and I was driving my car harder than just average driving.
But which do I believe?