anti freeze missing

[sonoma driver]

I lost about an inch of anti freeze over the past 2 months. This doesnt seem normal. So where can it go if there are no leaks under the truck. Any problems if I just refill every couple months?

 

 

2.8l 93 gmc sonoma 5 speed if it really matters

[GM-Tech]

Could be going INTO the engine (intake, etc.). External leaks can also be so gradual you might not see anything on the ground or may only happen intermittently or under certain conditions.