Drove roundtrip from Davis to Berkeley. Left car in the driveway in Davis. About an hour later, came out to huge puddle on pavement under radiator reservoir. Resevoir empty, some liquid spray visible under the hood. Refilled reservoir only to have water gush back out the bottom of the car. Obviously not driving it, what did I do/what can I expect at the shop? I am pretty capable, but I don't fix things I can't afford to mess up (i.e. my 2002 Volvo s40).

 

It might be simply a cracked hose. The simple method is to fill it with water and watch where it's leaking. With a large leak it should be obvious. I've had to replace several hoses over the years on my 2001.