Originally Posted by Superd
The coolant cant physically heat up and cool down in such a short period of time so it sounds like a faulty temp sensor. Should be an easy fix for the dealer.
Not always. If the thermostat is sticking sometimes (opening at a higher temperature than normal), it can give this illusion of overheating/rapid cooling as well.
However, a faulty sensor or grill shutter issue posted above is more likely.
2014 Mustang GT custom ordered to replace the GT500: Sterling Gray, NAV, Recaros, Brembos, Glass Roof, back up camera, 6 speed auto, loaded
2012 Focus Titanium - 18" wheels with handling package
2009 GT500 Shelby (700 rwhp) - sold