Advice on Drying a Car Interior

The leak is fixed -- but the car is still wet. The dealer or garage sorted the source, and now you are left with damp carpets, steamed-up windows and a smell that will not go away. Gary explains how to approach drying it yourself, and what to watch out for.

Take Mould Seriously

If there is a musty smell, there is almost certainly mould. Most people see it and think they can wipe it away -- but mould gets into your lungs, and the first symptoms are flu-like. You often do not connect the two. If there is significant mould in the car, you need a mask, not just a damp cloth.

The good news is that mould needs four things to grow: still air, darkness, something organic to grow on, and a damp atmosphere. Remove any one of them and it stops. Once the water is out and the car is properly dried, the mould will not come back. But it has to be properly dried -- not surface-dry, foam-dry.

Use an anti-mould product without bleach. Read the label carefully; some products use other words for bleach. Apply it while the car is still wet so it can penetrate everywhere the water has been.

Getting the Seats Out

In 99% of cars where the footwell is wet, the seats need to come out. Unbolt the seat -- usually four bolts, sometimes two, often Torx-head -- and unplug the connector underneath before you lift it. Important: once the seat is unplugged, do not turn the ignition on. The car will sense the seat is missing and may throw a warning light that needs a diagnostic reset to clear. If you have to operate a window, be aware of this first.

Seat removal is a two-person job. Guide it and lift it at the same time, and watch for seatbelts attached to the seat frame. Once the seat is out, undo the door trim and lift the carpet -- it comes up like wings, one side or both depending on where the water is.

What You Will Find

Gary filmed under the carpet of a Vauxhall with a leak that had already been fixed. The surface carpet felt damp. Under it: approximately 10 litres of water on the passenger side alone, the foam soaked through to the floor pan, wires sitting in standing water. The car had created its own small weather system -- the moisture was condensing on every cold surface inside and circulating. That is why the windows steam up even after the source is fixed.

Check any electronic boxes you find under the carpet. Some will have a part number you can look up with the manufacturer's parts department to find out what they do. An amplifier getting wet is a problem; an airbag control unit getting wet is a safety issue. If a safety-related unit has been sitting in water, it will likely need replacing and programming in by a dealer.

Drying

Wet-vac first to extract the bulk of the standing water from the foam and the floor pan. Then air movement -- a fan heater pointed at the open car works, but takes days. An industrial blower with a pipe directed into the footwell is significantly faster. The foam in deep footwells can hold a lot of water and takes time regardless of what you use.

Do not reassemble until everything is bone dry. Damp foam sealed back under a carpet will cause condensation throughout the car, and condensation affects electronics in places that were never directly wet. Once it is all back together, check after rain two or three times to confirm no water is returning before you are confident the leak is properly resolved.

If the job is more than you want to take on, see our carpet drying service.