It could be water pump, leaky radiator, hoses, head gasket, or just about anywhere else that the coolant circulates. You'll need to get under and find out where it's leaking.
"transmission fluid leaking from fitting below radiator cap after replacing radiator on 99 surburban
Probably your radiator fluid leaking out.
Antifreeze is green in color and is leaking from your radiator .
It is probably Radiator fluid that's leaking. if you have red radiator fluid. it looks purple when it heats up. I had this from my Toyota Sequoia when the leak went over the hot engine.
if you have an automatic transmission there should be cooling lines going to the radiator to cool the transmission fluid the lines could be leaking or the tank could be leaking
put radiator sealer in it or crack an egg in it
Green fluid leaking from a car is radiator fluid. "A professional certified mechanic can handle the repair or maintenance needed to fix this issue."
loose/cracked radiatior hoses
You will notice two lines going to your radiator from the transmission. One is a service line and one is a return line. The radiator has a transmission cooler built into it. If you have trans fluid in the radiator chances are the trans cooler is leaking. A little trans fluid in the radiator will not affect engine cooling BUT as soon as the pressure drops in that transmission you may very well have radiator coolant sucked into the tranmission and that will ruin a transmission in a hurry. You need to get this checked out as soon as possible.
bad radiator cap
Find where the fluid is coming out and repair/replace it.
You have a leaking transmission cooler, usually part of the radiator. The transmission fluid is mixing with the antifreeze turning it pink.