I went to Subway for lunch, got back out to my car and saw a coolant trail running down the parking lot. I went back to work ate lunch, let the car cool down and then checked the water in radiator and put in less than a 1 quart of water/coolant mix. Temp guage not over 180 degrees, however, I run a Derale temp controller.
Drove home after work shut it down same thing, leaking again. Let it cool down, put in some water.
Turned off Derale to run factory setup, let the car idle through three cycles of reaching temps of 220, watching for coolant leak, nothing. Shut it down and then it starts leaking.
It only leaks when I shut the engine off. It looks like its leaking from the lower radiator hose, however, seems like it would leak all the time if it were a hose. Any ideas? water pump or hose?
No noise from water pump.
Thanks

 

waterpump