This might help! After stripping the carpet out as well as the under-dash panels, a friend and I hosed the car down all around the drivers side, windscreen etc, and discovered that water was ingressing through the dash, dripping down into the cable channel and then being soaked up by the carpet. We located the leak to the pollen filter caps! Basically the foam/rubber backing to the plastic caps had 'gone', allowing water to come in and soak the pollen filter, which in turn dripped it's way through what looked like the blower blades finally working it's way through the dash and onto the floor. I've replaced the caps on both sides with new ones, and no more leaks! So I ended up having a dual problem - the o-rings definitley had gone, hence the coolant, but this was compounded by rain/car wash water getting in as well.