my dad used to have an old AMC concorde (what a piece of shit that car was), and whenever it rained, the passenger side floor would always be soaked. i never quite knew where it leaked from, but feel around the door jambs and other areas in the car to try to find where water may be from.
if it is the coolant thing as suggested by chuckles, then get your car into the dealership and have them fix that immediately. that could potentially leak coolant into the oil, which will screw up the oil very badly, and could cause your motor to seize and the only way to truly fix a seized motor would be to replace it.
2011 Taco ACLB, 5mt, 4x4, MGM
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