well i'm in new mexico, its dry as fuck here, so i don't think it would be from moisture in the air. the seal on the cap is good and its not leaking anywhere.
dsm/mitsubishi service manuals https://www.mediafire.com/folder/5k14qlaulb9s1/dsm_mitsubishiservice manuals(my whole collection) https://www.mediafire.com/folder/ac51jwwa3g1n1/automotive_manuals