Did you mean back of the engine bay? Coolant would not be leaking from the rear of the vehicle as there are no coolant lines back there. A coolant leak in the rear of the engine bay can indicate heater hoses, or the block could could be porous, or the headgasket could be leaking. Do a coolant pressure test (apply the recommended pressure on the cap and let it sit) and see how much psi you drop over 10 minutes. You shouldn't lose more than 1 psi. If you find youre losing pressure faster than that, apply pressure again to cap spec and look around with a flashlight to see if you can find coolant dripping from somewhere