If coolant is "disappearing" and not leaking out, it is probably escaping as steam or vapor from the coolant recovery tank. This tends to concentrate the ethylene glycol in the anti-freeze system. If you are "adding coolant," make sure you are replacing water, if you are losing water, and coolant mix if you are losing coolant mix - these are different situations. Too high a level of anti-freeze actually hurts the heat transfer and anti-freeze properties of the coolant fluid! Use a cheap specific gravity type coolant gauge to see if the concentration is optimal. If not, add the proper fluids.

 

I refilled mine on my own, although the replacement was a greenish color. IDK! I"M FRIGGIN COLOR BLIND! Well It was green to me. SO yeah. I had to refill it at 11,500 miles on it and now it's doig just as good as new, except for with all of the mods I have.