Coolant leak on 94 ranger

Hey everyone, last time i posted here i had good luck and fixed the problem - so here we go again. i seem to have a coolant leak somewhere - i changed the oil yesterday and while i was at it i topped off the coolant in the recovery tank to the cold line. Took the truck out for about a half hour then parked it over night. when i came out this morning i found a pretty sizable puddle on the ground, seeming to originate from the drivers side, and when i checked the radiator it was low but the coolant recovery tank was full past the cold line…i let idle today for about a half hour then let it cool down trying to catch it in the act but saw nothing. if i trace the source of the puddle it seems to be coming from the cap area or at least that side of the compartment. would this be the radiator cap itself? allowing coolant to boil over and out but not get sucked back in? since ive had the truck i have noticed a small, very small, amount of coolant on the ground now and again but this is the first big puddle. thanks again guys

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