my car smells like Engine coolant

2 weeks ago, smells like engine coolant....its like 10X stronger than engine coolant but the smell is the same. I could only smell it when the air control is turn to "out side to inside"mode i cant smell it when it is slided to the recirculating mode. So i took it to a shop...the nice mechanic checked it out and said i was very long on engine coolant so he pour Water, i think, in to my radiator and the overflow tank for free and told me that there might be a leak. about a little bit more than a week, my check coolant light came on again and my coolant is low, so i fill it up with coolant.......

i have 3 questions,

1: can i put water in instead of coolant since its summer and it wont freeze?

2: Every time i turn the engine off, i could hear the coolant making some bubbling sound, i never hear that before, is this my problem? is my car burning coolant or leaking ? because i cant see any coolant on the ground when i parked also, my exhaust smell very normal.

3: is this related to my check engine light that came on 2 days ago?
becuase i could hear the car ping when i accelerated sometimes.

Don't use pure water as it will overheat in the summer. Coolant is always recommended. If you smell coolant you have a leak somewhere. If there is no steam coming from the exhaust then the leak can be in a couple of other places. The first thing that comes to mind is that the heater core is leaking. Check the carpet in the front seat for moisture. Sometimes the antifreeze will leak into the passenger compartment. The other thought is that you have a bad head gasket but you would have other signs such as poor performance and etc. The check engine light could be an indication of water in the combustion chamber that has destroyed an O2 sensor or a plug. Pull the plugs one at a time and see if one is wet. If it is then that may indicate where the leak is. If you need to replace the head gasket it is not too difficult to do but will take time and some money. You may even want to use Bar's Block seal that is designed to repair leaking head gaskets.

I forgot to mention i only smell the coolant when my coolant is low but after i put the coolant in, i dont smell it any more from the vents. Thanks for posting the ebay link for the code reader, GTP DAD. I might get that one since its so cheap.

No problem. By the way those readers will work on any car with an OBDII computer. They are not car specific.