You basicly have 2 posibilitys here:

A. It's leaking (onto the ground or hitting something hot and evaporating prior to hitting the ground.)
B. You have a blown head gasket (causing it to consume the coolant and probably burn it up prior to shooting it out the exhaust.)

check your oil, if you notice that it's milkey looking then you have a blown head gasket.


Check around the car for leaks comming from your coolant hoses.

There are only 4 MAIN coolant hoses
- to and from your radiator
- to and from your heater core (ports located at the firewall)