My temp gauge doesn't go above half, ever, so I don't think my engine is being damaged. When I got home today, I popped my hood and saw my resevoir tank filled almost to the top. The radiatior itself was just barely warm to the touch, and the lower radiator hose was cold. I've replace my thermostat 2x in the last 4 months both times with oem parts.

Could this be caused by a broken water pump?