Engines hold a lot of heat. It would take 30 minutes for a stopped overheated engine to cool to normal running temperature.

AC can cause an engine to overheat if the condenser (like a radiator) is in front of the engine radiator. If it’s side mounted, then it won’t.

Water pumps fail at the bearing, causing leaks, or the plastic impeller can disintegrate causing loss of water flow and over heating. But it’s not intermittent. If you remove the overflow tank cap and water is flowing, then the pump is working.

Fans help move air at low speed driving, but don’t contribute much at freeway speeds.

__________________
2005 X5 4.4i SterlingGrau, Sport Package, DSP
Build 3/12/2005