Hello! I am new here and will admit to being a female who knows very little about cars, but had no where else to get info from. I just recently had to purchase a used (obviously) car because the engine just blew in my 99 Explorer and unfortunately I had just spent over $1000 in repairs on that one before finally giving up as the car wasn't even worth that much to begin with. Anyway I purchased this 2001 Explorer Sport and it seemed to run fine and all that (wasn't expecting perfect for an almost 13 yr old car) but it has started to do strange things and I need help figuring it out. I first noticed the Antifreeze overflow tank was pretty much empty, so I filled it and checked it the next day and it was empty again. So I filled it again before bed and got up this morning and it was empty again? I am hoping its just a cracked overflow tank but wanted to see if anyone had any other ideas for me to check? Also it has a rough idle when sitting at stop lights , almost like it wants to stall and slightly stutters when pulling away. It has never actually died on me yet but I want to address that before it actually does. I am probably being overly panicked but since I got stranded twice last month and then the engine blew finally in my old car, who could really blame me? Any advice would be greatly appreciated!

 

Could be a hose or bad water pump too...

 

Something like this can't really be diagnosed easily over the net.
Some of the steps to consider having done would be , a compression test to determine cylinder health and integrity and that could include head gaskets, defective head or engine block. Spark plug removal and inspection might show which cylinder(s) are possibly involved. We don't know at this point where the coolant is going. To jump to any conclusions without some tests to verify the exact cause could run into unnecessary expense. The coolant could be going into the oil system (pan) and without checking it could result in some serious engine work. If you decide to have it checked and the solution sounds expensive you can and should always get a second opinion from a reliable shop.