Sudden overheating problem PLEASE HELP!!!

Today I was cruising down the highway about 80mph and noticed the engine light come on and looked at the guages as I saw the temp was in the red. I immediatly pulled over and shut the engine off. Popped the hood and noticed a little coolant not alot on the passenger side. There is still coolant in the resevoir. After I got it home and it cooled down I started it back up. All fans work. Couldnt see any leaks. The top hose on the driver side was very warm but the lower hose on the passenger side was not? Also no heat comes out the heater? Could this be a thermostat? Any other ideas and tests I could perform would be greatly appricated.

Thanks,
Charlie
1994 325i
190k miles
I have had the car for about 500 miles.

Hopefully the thermostat is mostly frozen shut or maybe a huge air bubble in the system.

You say that there is a small quantity of coolant on the passenger side? Where is it coming from? If it were leaking around the water pump then I would suspect the water pump is junk.

Have you checked the coolant level in the radiator itself when the car is cool?

The small amount of coolant seems to have come from the lid of the radiator cap, Im guessing it just overflowed during the overheat. The car is now cold and the coolant level is still at a good level.

when this happen to me it was the thermostat

Thank you for your input. Im confident that the thermostat is the problem now. I will replace it this weekend.

Crap!!!!!! I replaced the thermostat which did need to be replaced because it was broke in two peices. But it is still overheating????? How do you check to see it a water pump is working? Im assuming that would be the next step?

Fixed it! The water pump was shot.