My car is leaking antifreeze onto the ground under the reserve tank. It is not overheating and of course after the coolant has leaked out my low coolant light comes on. I added more but there was still some in the reserve tank..

you have a blown head gasket.. doesn't have to have coolant in the oil for a blown head gasket... if hoses are rock hard when running then you have exhaust leaking into the coolant via a blown head gasket...

COOLANT-ADDING ADDITIONAL
Do not remove radiator cap to add coolant to system. When adding coolant to maintain correct level, do so at coolant reserve/overflow tank. Use a 50/50 mixture of ethylene glycol antifreeze containing Alugard 340-2 y and low mineral content water.
Remove radiator cap only for testing or when refilling system after service. Removing cap unnecessarily can cause loss of coolant and allow air to enter system, which produces corrosion.

COOLANT LEVEL CHECK
The cooling system is closed and designed to maintain coolant level to top of radiator.
WARNING: DO NOT OPEN RADIATOR DRAINCOCK WITH ENGINE RUNNING OR WHILE ENGINE IS HOT AND COOLING SYSTEM IS UNDER PRESSURE.
Remove radiator cap. The coolant level should be to top of radiator. If not, and if coolant level in coolant recovery bottle is at ADD mark, check for:

• An air leak in coolant reserve/overflow tank or its hose
• An air leak in radiator filler neck
• Leak in pressure cap seal to radiator filler neck

TRANSMISSION and OIL LEVEL CHECK TUBES


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It could be a slow leak in the radiator or hoses or the head gasket. The antifreeze could be blowing out of the cylinders rather than leaking to the ground.

You may want to check your manual. There is usually a light to tell you the coolant level in your reserve or overflow tank is low, and there is another light to tell you the system is overheating due to not enough coolant in the entire system. Nonetheless if either light remains on and you have refilled the overflow/reserve tank it is time to look for a leak. Leaks can be at hoses, in gaskets, and other locations. A puddle on the floor where the car is usually parked can help you locate a cracked hose or loose clamp, an antifreeze smell in your exhaust can help you locate a much worse problem.Often you may detect an antifreeze smell only after the car is warmed up which can be a leak which is running onto an exhaust pipe.

your water pump is starting to leak from weep hole

Most vehicle Mfg.'s do not want you to access the radiator, so they put in overflow tanks.
You can add coolant there. You will find it under the hood next to the interior fender.
Only check or add coolant when the engine is cool.
I would start looking for a coolant leak. Vehicles are not supposed to leak or lose their coolant.
Check for green coolant spots on the ground where you park your vehicle.
Please let me know what you find.

Inside the coolant reserve tank there is a sensor for coolant level.


Over time,this sensor can get stick.


Inspect the coolant reserve tank for crack or leak.

Locate the coolant level switch/sensor and soak it in clean warm water.

Make sure it's free to move up and down the float path.

Top off the coolant tank with coolant only.

Check your hoses entering your block and radiator. you may need to bring your vehicle into a garage and ask for a "Pressure Test" this will indicate if you have a crack or leak.
Good Luck.

check the condition of the reserve tank and the hose from the reserve tank to the radiator for leaks if no leaks there have the Radiator cap presure tested . also this could be a air lock in the engine if the radiator is new with the engine running and the heater on hot observe the fluid level in the radiator with the cap off if it drops as it warms add more coolant this will purge the air .

Is the reserve tank cracked or have a deteriorated hose going to the radiator? Remove the tank to find out. A bad seal on the radiator cap can also lose fluid. A coolant leak anywhere can deplete the coolant level in the radiator and reserve tank. Check your owners manual for antifreeze type and mix ratio with water.