I have a 1990 525i with the radiator and h2o pump replaced last year.

I get a coolant level indicator on. When the engine is hot and I open the radiator cap (a "no no"!), the level is 5 inches below the cold fill level but then it quickly fills up 4 inches above cold level line on the expansion tank with a slurping / gurgling sound.

I bleed all the air out with the engine off, only coolant come out the bleed hole at running temperature.

What is wrong and what can I do?

"Let it Bleed"
Littlematchgirl in Czechago, Illinois