I did a search through the billions of coolant problem threads but didn't come accross this one.
After taking the car for a drive the coolant level in the overflow tank goes up by a few mm's, which is quite normal. But when I then shut off the engine in one burst the coolant level in the overflow tank rises by about 1/3 of an inch. After the engine is completely cooled down everything is drawn back into the radiator.
Is this normal? Never noticed this on any other car.

 

That is exactly what the overflow bottle is for. As long as it's getting sucked back in everything is cool.

 

mine did that then slowly it overflowed out under the car and a coolant seal went. Its running hot for a reason