Nissan Note Water Leak: With DIY Advice

This 2009 Nissan Note had a replacement windscreen -- noted from the start. The owner had found the passenger rear footwell wet, and the rear of the car had old stain marks suggesting water had been in there before. James was training Edward on the 28-point check during this job, demonstrating why you always check the known weak points on the specific model rather than just the obvious symptom.

James put air behind the windscreen seal. The bubbles came through immediately: the screen replacement had not been properly sealed. Underlay underneath the passenger seat was soaking, polystyrene blocks in the floor wet through. A rubber grommet at the rear was also letting water in. The rear lights were not actively leaking but on a 2009 Nissan Note, James recommended resealing them preventively -- the locator gaskets perish on these cars and if they start leaking after the other repairs are done, the whole job has to come back.

Fixed: windscreen resealed, rear grommet sealed, rear light clips and gaskets resealed. Interior dried. Car left clean and dry.

DIY guide: drying a wet car after a water leak

Gary uses the drying section of this job to make a detailed DIY guide for people who want to tackle the drying themselves after fixing a leak. The steps below are based on what we do professionally -- scaled down for a domestic setup.

Before you start: mould

If there is visible mould anywhere in the car -- headlining, seat belts, behind the seats -- deal with that first before moving anything. We use Formula 429 (Chemspec), a hospital-grade product. Whatever product you use, choose one without bleach. Pull all the seat belts out; mould is almost always on them if it is in the car. Wear a mask when spraying. Mould gets into you through your nose and mouth -- do not sniff around looking for it.

Getting the seat out

You need to get the seat out and the carpet up. There is more water under there than you think -- the foam and polystyrene absorb it and do not give the surface any visible sign. Leave the carpet down and you have not solved anything; the water is still there corroding the floor and growing mould.

Seat bolts: Nissan Notes use a cover over a standard bolt rather than the star-socket type. Order spares from the dealer before you start -- a couple of extras in case one strips. They are not expensive and having them means you can put the seat back together correctly. If you are ordering a new gasket for a rear light while you are there, get the seat bolt covers at the same time.

Move the seat fully forward to access the rear bolts, then fully back before lifting it out. The slide handle is right where your hands will be -- if you pull it accidentally while lifting, the runners release suddenly and the seat can move unpredictably. Sheet the door sill with a towel before you lift; scratching the car with the seat on the way out is an easy mistake. Two people, legs straight, back straight when you lift.

Disconnect the seat plugs underneath -- these are the wiring connectors for the seat weight sensor and seat-belt pre-tensioner. Once the seat is out, note the airbag control unit: if it is wet or submerged, it will need replacing. A damp airbag control unit is not just an airbag light -- it is a safety issue. Replacement units are not expensive; get a new one and have the garage reset it (about 25 to 35 pounds, 20 minutes).

Getting the water out

Wet vacuum first. Suck out as much water as you can, come back in an hour, suck out more. Keep going until you are getting very little out. A good old bath towel wedged under the carpet and squeezed out does a lot of the initial extraction. You are trying to get the bulk of the water out before the heater goes in.

Once the wet vac has done its job, spray antimicrobial product (Formula 429 or equivalent) under the carpet while it is still slightly damp. It mixes into the remaining moisture and penetrates the foam -- more effective than spraying when everything is dry.

Fan heater: point it at the wet area. If you can supervise it, run it on hot. If you cannot supervise it overnight, turn it down to warm -- you do not want it to topple and cause a problem. Leave one window open a crack to let the damp air out. Do not leave the interior lights on; they will flatten the battery. A residual current device (RCU) on the extension lead is good practice -- about £15 on eBay. The lead should not be somewhere someone can trip on it and pull the heater.

Move the heater around. Work both sides if both sides are wet. Budget two to three days per side for typical thick foam underlay. Come back, check, if it still feels damp get more water out with towels and keep the heater going. When it is dry, pour a small amount of bicarbonate of soda under the carpet before putting it back down -- it absorbs any residual odour.

Putting it back together

Make sure the seat belt reels are not mouldy and that any electronic units near the water line are dry and working. Lift the seat back in with two people, seat belt can stay connected while you pivot it in. Reconnect the wiring under the seat. Bolt it back down -- make sure you have the correct socket size, going square onto the bolt, and torque it properly.

Reset the airbag light. When you disconnect the seat and reconnect it, the car records the event and the airbag light will come on. A diagnostic tool (OBD scanner with airbag reset capability -- spend at least £100, the cheap ones do not work on airbags) can reset it in a few minutes, or take it to the garage for 25 to 35 pounds.

If your airbag light comes back on after resetting, something is still connected incorrectly or a component that got wet needs replacing. Do not ignore it.

Good luck. Wish you dry driving.