Originally Posted by kainers
I drove it about 10 miles, it was pretty chilly out, and I have an electrical fan. Dunno if those are any factors.
It should usually get up to temp within 10 miles, but not always. But low coolant will NEVER cause it to run cold. It will work like normal until it gets low to the point where it can't curculate through the engine and then it will overheat right away.
I would fill it up with a 50/50 coolant mix and fill the reservoir as well. But as far as it running cool from being too low... it just doesn't ahppen so I'd say you're fine.
If you have an electric fan and it was running all the time in cold temps I could see it only running around 1/4 of the way up. Or your thermostat could be stuck open as well. None of those things will hurt your jeep though. Running cool isn't going to do immediate damage to your engine like overheating, but I'd still check out those things as soon as possible.
If it never gets up to temp I'd start by checking the thermostat. They are cheap.