2014 Jeep Patriot Limited 4 Cyl 2.40L
What can cause my coolant temp gauge to rise?
So about a week ago the coolant temp gauge started rising on the dash. It rose between the 1/2 and 3/4 mark lines. So I cut the heat on and it dropped. I popped the hope and seen the coolant resevoir was about empty. I filled the reservoir and it ran fine. So a week later, today, it started rising again so I kept going without turning the heat up and it stayed there, so I cut the heat on. It lowered. I got home and popped the hood to see if the reservoir lost any coolant amd it didn't. It was still full. So my question is what could it be that is causing this?