Well I picked up a 6.4 last night (my first one) with about 250k for about $9k which I thought was a good deal... Anyway even after driving it for like 45 minutes the coolant was like barely in operating range, the truck was running very cool, heat worked great, just wanted to make sure this is normal or????

 

Without getting an actual temp just going off the gauge it's hard to tell what it's really running temp wise.

 

I'll have to plug my scan gauge in and drive it around, I'll have a reading in the next couple days

 

Sounds like you have a wiring problem, a bad sensor, or bad thermostats.