Dropping Coolant While Driving

[MWS]

I'd also vote water pump...pull the front engine cover and check around pump for leaks and generally check/test workings of pump. If you go so far as pulling off the pump, check to make sure the impeller is intact....if not, you need to do a system flush (or a couple).

[BirdDog]

Originally Posted by MWS

..if not, you need to do a system flush (or a couple).

... to get the broken/missing impeller vanes out before you suffer a cracked head...