BMW 320

1989 BMW 320iA.

I had a problem with the cooling driving home from work yesterday. All of a sudden the engine began over heating and the coolant tank started spewing all the fluid out a valve in the tank cover. I shut the engine down to let it cool off. Replaced the fluid and started it up again. The same thing happened. I gave it one last shot this morning and everything was fine? Was able to drive to work. Any idea what this would be? What parts need replacing?
greatfull for any input!
May 5, 2006.

Sounds like a sticky thermostat

Sep 12, 2006.
I have a 1998 528i. For some odd reasons, my water meter (or thermometer, I don't know what to accurately call it) is going out of control. Nonetheless, I noticed a pattern in its behavior: When I am driving at high speed like on the highway, there is no problem, it is right in the middle where it should be, but if I slow down or halt at a light or in traffic or park, the gauge temperature gauge slowly increases until it gets to red. I don't know what to think of it. I assumed that the fan wasn't working but when I open my hood, it is still turning. I don't know if there is a connection problem or my 02 sensor has something to do with it.
Please help me before I have to spend the big bucks trying to fix this issue.
Thank you very much.

Nov 15, 2006.