Water damage to carpeting and want to polish concrete floor underneath instead of new flooring. Is this possible?

You did not indicate what sort of climate you live in or exactly where the carpet in the cabin was most wet...

However, the most common source of water inside a car is a clogged HVAC (heating, ventilation, and air conditioning) drain tube. This tube provides drainage for water condensing on the AC evaporator and any water that enters the HVAC system during rain storms. If the tube is clogged with dirt and debris the water drips from underneath the dash where the heat vents are ... onto the floor instead of dripping onto the road. So usually the wettest place on the carpet is the front passenger foot well.

The drain tube is generally located on the firewall, low on the passenger side. You would probably have to raise the car to see/reach it. I am not sure exactly where the Passport one is ... they can be hard to find at times.

Other possible sources of water are a clogged sunroof drain tube, leaking window seals, torn or missing door seals, and clogged door drain holes.

Also ... buildup of debris (pine needles/leaves) where the windshield wipers retract in to can also block those drains which can sometimes cause overflow into the passenger compartment.

After you find and eliminate the source of the water you will have to lift the carpet and remove the padding underneath in order to dry it. The padding holds water like a sponge and will not dry unless it is removed from the vehicle. Shop vacs won't get the water out of the padding. Even if the carpet feels dry the padding underneath may still be wet, and that is where mold and mildew grows.

Helpful?

Good luck on your troubleshooting

it can be done as most what is termed "marble" products is polished concrete
talk with a masonry business as to how it is done but from what I have seen it will be a lot of "elbow" work with out power tools

Most cars have a set of rubber plugs conveniently located under the carpet and they go through the floor. You can pull them out from underneath the car, or at worst, by pulling off a couple of panels to get to the carpets. They are usually about 1.5 inches in diameter. If you leave them out of the car for a couple of days depending on the weather, the water will dissipate.

the drain plugs are located under the floor mats in the floor pan . If you look from underneath you will see the round plugs .If the carpets have been wet that bad then you will never get rid of the musty ( fungus) smell . consider new floor mats

This can be from one of couple sources. One would be a broken or missing rubber seal in the firewall. Water can and will enter the passenger compartment if the seal is not good or missing. The firewall is the metal between the engine compartment and passenger compartment. There are many penetrations in the firewall for throttle linkage, steering column, electrical harness, etc. All of these penetrations have seals to prevent water from entering. Check to make sure all penetrations have seals. Inspect from under hood and from under the car, too.

Another source is damage to the floor pan. If you went over a rock or jagged object without having enough clearance, it may have punctured or even sliced through the floor - under the carpeting and sound deadening material under it. If you live in a cold area, and the roads are treated with salt or chemicals to melt ice, it may have caused rusting holes to appear in the floor pan. Water spraying up from tires would enter through the puncture or slice and the carpet would wick the water in. It would take a long time to dry and give a musty smell after just a short time. You should inspect the floor pan from underneath the car. Look for punctures, slices and rust / rot. Clean and seal any openings found in the floor pan and firewall.

Fixed windows and glass in the car body are also sources for leaks. The is especially true if glass has recently been replaced. Many times, the back window leaks into the trunk or metal under the rear seat - and flows to the carpeted floor. Look in the trunk at the bottom of the rear window. Side windows can leak, too - so don't forget to look behind trim interior panels on the sides of the back seat. Your leak could be coming from the windshield, too - this will be harder to locate through the dashboard - but you may find water dripping from wires, etc. Look for evidence of water / rust. Clean and reseal body / glass joints when found.

Good luck!

For my 1996 E350 15 pass Club Wagon, the Bench seats mounting brackets to floor hex head(3/4"/19m socket) bolts are: 2" Long(w/ 1 3/4" shaft), bolt size is M12(1.75 threads)(Available at Lowes I believe in specialty drawers).
Also the seat belt attachment torx bolts are size 7/16" (20 threads count).
For me, I've removed all but 2 bench seats and repositioning them side ways. One along the wall behind the driver's seat and the other along the opposite wall towards the back on the passenger side.
This way, it's now an 8 passenger party road trip lounge van comfortable seating.
I had to drop the gas tank(had to anyway to replace the filler hose) and drill new holes and buy new nuts and order mending plates 9-in x 3-1/8-in 20-Gauge Galvanized Nail Plates at Lowes.
I'm going to weld the nuts to the mending plates after I drilled them as well and rivet the mending plates under the van floorso that the seats have a similar factory floor anchor strength for a collision. I found I was able to use still 3 of the original shoulder seat belts with the new bench outboard seating locations.

Hope it helps

1. Have you been using your heater and is the smell sticky sweet? If so you're heater core might be leaking.

2. Have you been using you're A/C? If so you may have a clogged or disconnected condensation drain.

I think that I can help you. It sounds like your drain-tube is plugged up. Get in the passenger side, and pull the carpet back from under the glove box. Look for a black rubber pipe that goes from a black box, and pokes thru the firewall, on the passenger side. Remove the hose from the box, and have a container ready to catch water. If water comes out of the black box, your drain hose is plugged up. Clean out the clog, and you will be golden.

Have your ac evaporator deain cleaned out or checked. Without this working the ac water will collect there.

sounds like a heater core