Hello,
I bought this car about 5 weeks ago, it's a 4-speed automatic 4 door ls at ~215000 miles. At first I was hearing a boiling noise when accelerating on the highway so I took it to a mechanic. They replaced the timing belt and water pump, and did a coolant flush and the sound was gone. They also said I had oil and coolant leaks so they supposedly fixed that. 3 days later while I was driving the car overheated and shut itself down. I took it to the same mechanic and they said I overheated and got a blown head gasket and need an engine replacement. They didn't give a reason for overheating. The car at that point was running for a while (5-10 mins) and then dangerously overheating so unusable. So I towed it to another mechanic that was recommended to me. That mechanic got the bypass hose replaced (said the overheating was due to it breaking and leaking) and got the car running (without overheating!). And he said my head gasket is fine and there is no need for engine replacement. The problem is, when I came home I saw coolant dripping under the car. i tried driving a few more times and every time I reach my destination and shut the car off, it starts dripping. I since topped off coolant in my reservoir and realized the leak becomes less when the reservoir is about less than a quarter full. I also see a bit of coolant on my coolant reservoir cap, for some reason. see here: https://imgur.com/a/zEFOuUt. I'm thinking it is broken (there is actually a gap, see the picture) so I ordered a replacement. Currently the reservoir is about a quarter full and the coolant drips only a few drops (think about 30-50 mls) after every drive. I actually took it to the mechanic to show the problem and it didn't drip at all for him to see so he just said there's no problem.
So, thanks if you've read this far. Do you have any advice to me? The second mechanic insists it's not the head gasket. I don't have milky oil. I just need a car that can get me from A to B without dangerously overheating. attached some pics for you to see.

 

Replace the cap that's where the leak is coming from its very common.

Make sure the radiator is bled of all air! ~ You can do this yourself with a simple jack.

Jack the front of the car as high as you can.

When the engine is cold siting overnight remove the radiator cap and top off the coolant to the top if it is low, do the same to the reservoir top it off to the full mark and close the cap.

Leave the radiator cap off and start the engine.

Turn the Heat in the cabin to full or High!

Use a funnel in the radiator cap to so it doesn't overflow.

Let the engine idle and warm up.

Watch the radiator fluid for bubbles and wait till they stop coming up,

The radiator fans should turn on and off about 2 times and both radiator hoses should be hot.

Once that's done put the cap back on and lower the car and turn off the Heat in the cabin.

The radiator should be free of air, and you should not overheat.

If you continue to see coolant the next day on the ground, then investigate where its coming from.

 

It's actually possible the radiator cap is not allowing air to vent and this is pushing coolant out the reservoir. It's also possible exhaust gases and pushing out. I would try a new cap first. If not fixed then have a compression test done to clear the head gasket as still being good.