How to Fix: Car Water Leaks

Got a leak? Well, if water’s getting into your car you need to act fast because not only can dampness ruin an otherwise smart interior, but it can also inadvertently rot out floors and sills. Moisture inside doesn’t do your car’s electrics any favours either – if circuit boards and crucial electrical connections corrode, you’ll be faced with all manner of spurious faults which can be tricky to trace.

Never too late

As always, prevention is better than cure so try to prevent water ingress before it happens by carrying out regular checks and replacing rubbers etc. as soon as you suspect a leak. However, it’s never too late to stop water getting in – and in general, it’s all stuff you can tackle yourself. Watch out for rust bubbles like this around a Mk2 Golf rear screen seal, these can often lead to the source of your problem.

Rubber lover

There’s a good chance that water will be getting in via an aged or damaged body seal that no longer keeps out the elements. If this is the case, carefully remove the old rubber and replace it – door rubbers are available for virtually every model. A good tip here is to warm the new rubber first with a hairdryer to make it easier to fit. Oh, and if the water’s still getting in check the fit of the door itself and adjust the latch mechanism if necessary.

Perishing thing!

As soon as rubber ages and begins to perish there’s a risk of it letting in water. The bottom corners of the windscreen rubbers are where they let go first. Sometimes rubbers can leak here too if they don’t fit the profile of the bodywork properly following poorly executed repairs. If this is the case, have it done properly and fit a fresh new rubber to create a perfect seal. Also, watch out for rust (and holes) being hidden behind a rubber seal – that could lead to you needing a special repair panel.

Chamber of secrets

Lots of cars have what’s called a plenum chamber which sits between the windscreen and the engine compartment, typically where the bonnet hinges are and quite often where the battery is located. Now the problem here is leaf debris can collect in the bottom and, if the drain holes get blocked, water can spill into the car’s cabin. The solution is simple; keep the chamber squeaky clean and the drains clear so the water can get out. Be aware of perished or split grommets that carry wiring through to the cabin. If these have been compromised you’ll have a footwell water feature in no time.

Hole in one

Wondered why your carpets are always soggy? Well, it could be that rust has eaten away at the metal beneath and inconveniently created a hole. Lift the carpets to see if this is the case and determine where the water’s getting in. There are two solutions here; either weld in a small patch or better still cut out the affected area and fit a proper repair panel to keep your carpets dry. Also, be sure to remove any wet underlay – it’ll never dry properly in situ, and that stuff smells when it starts to rot!

Down the drain

Sunroofs are great, but if their drain holes become clogged, water can work its way into the car. Again, regular maintenance comes into play here – keep everything clear and you won’t have a problem.

Soft Top Shower

It’s fairly obvious that if you have a car ‘without a proper roof’ you will be more used to mopping up after a downpour. Take a few minutes to inspect the condition of the roof seals, and also try and get a friend to help you diagnose where it is coming in. (You get in the car, and they use the hose on the outside.) This method can save you a whole lot of time and towels! You can find new Golf Cabriolet and Beetle Cabriolet roof seals online here.

Scraping through

Finally, don’t ignore perished window scrapers. When the rubber on the scrapers no longer makes contact with your door drop glass, water can seep down inside the door. Now, this might not always be a problem but if the drains in the bottom of the door are blocked or if the door card membrane is damaged, water will get into the footwells and cause a flood. A new plastic membrane is a cheap fix, and it costs nothing to poke a pin through the drain holes every now and then.

A car that’s damp inside isn’t nice, especially at this time of year, so address these issues now to keep things nice and dry and prevent future headaches.

Best of luck!

Heritage Parts Centre delivers quality parts for VW and Porsche enthusiasts worldwide. Check out our car parts website here and follow our fun with #driveheritage on social media.


  1. Re. the plenum chamber; I’ve found that the Golf 3/Vento can admit water from the chamber into the passenger footwell via the heater intake surround/pollen filter housing. Especially if the car’s parked facing up a steep incline – water pools behind the housing before it reaches the level of the drain opening for the chamber. If the seal isn’t good, this will get inside.

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