cold
pop hood (bonnet)
start it and just stand there and watch for 10mins.
the answer might be real obvious.
see water pump spraying.
see hose spraying
even the rad can crack a tube and spray fluid. ( mine did in May)
it is under pressure 12 -14psi when warm and this fact will make finding the leak real easy. let it tell you.
if this don't work , then a new cap and thermostat.
Look in RAD is the liquid green and clean or do you see black carbon dust floating and or oil signs? (head gasket)
explain no rad fluid.? please.
does that mean, none in overflow bottle or none in the radiator with cap off COLD !
over-heating-why?
do a compression test.