My car is overheating when in traffic and losing coolant. The water is going into the driver side floorboard. It is the coolant water, you can smell it. The heater core has been by-passed to see if that was the problem. Any idea what the problem could possibly be? There is no leakage on the outside of the car except the a/c water.

SOURCE: Heater not dispersing hot air

There ia an actuator that controls the flap to change from hot to cold. You have to pull the bottom part of the dash and the whole blower motor housing. The part you are looking for is located just behind the radio and has an arm that goes into the heater core line. That is the piece you need. Its around $165 dollars and a dealer only part. And hope you have someone that can do it because mitsubishi charges over $500 in labor.

SOURCE: car is overheating and windshield is fogging up

If your smelling coolant in cab, and window fogging up, check fog if green heater core is going. Over heating could be a couple of things, plugged radiator, water pump, thermostat. To check for water pump Find the top hose, run car check for leaks on ground. While warm or hot wear glove oven mitt or something that you can feel through but will protect from heat, If you feel flow of coolant more the just a trickle its a good thing to replace thermostat. Also check for bubbles in the coolant tank, if there are bubbles your S.O.L. the head gasket is blown

SOURCE: 1993 Cadillac deville: Windsheild

sound right to me. check your coolant level

SOURCE: 02 Eclipse; heater doesn't work; wet floor inside; coolant drip

Your heater matrix has fractured.Suolution fit new matrix.Or you can have it bypassed.But you want get any warm air from the heater if its bypassed.But it will stop the water entering inside your car.

SOURCE: water on passenger floorboard when AC is on

You have a bad "heater core". It will leak inside, and outside once the enclosure fills. You need to replace it, or bypass it before your engine overheats and causes a lot more damage. If you're driving the vehicle daily, make sure you check and fill your coolant before you drive it.