Hi guys,i hope somebody can give me some advice on what it could be.As i was driving back home from work today the coolant heat level went up nearly to the red point,and a weird thing is that when i put the heating on it was blowing cold air,it is a 20 minutes trip from work to home and is mainly on motorway,when i got home and parked the car,in matter of seconds the the coolant heat level went down to normal levels. I am attaching 2 photos with the water heat levels,first was taken aprox 10 minutes after leaving work and driving on the motorway, and the second one was taken aprox ten seconds after i got home and ive parked the car,with the engine still runing.
Thank you


Photo 1

Photo 2