Used convertible cars: what are their downsides and what to avoid

• What keeps used convertible prices low?
• What to do if your roof goes wrong
• Looking after your roof
• Are convertibles much cheaper to buy in winter?
• Should I buy a convertible?

When the sun finally makes an appearance, us Brits like to make the most of it. Along with impromptu barbecues and visits to the seaside, we love being able to drop the roof of our car and drive with the wind in our hair.

As a result, there are over a million convertibles on Britain’s roads and we are willing to pay a steep premium for these cars when they are new. A Fiat 500e cabrio costs £3,000 more than the hatchback, while at the other end of the scale, Aston Martin will expect an extra £14,000 to take the top off your DB12.

Once convertibles enter the used market however, the premium starts to shrink, and in some cases the drop tops are worth less than the coupe equivalents as they start to age.

What keeps used convertible prices low?

The reason behind this is the potential cost of repairs if something goes wrong. Some cars have a dodgy roof reliability record which means traders steer clear. Once a big bill arrives, owners will want to get rid of them too, while insurance companies will quickly write off a convertible if the roof is damaged by an accident, break in or vandalism.

But there are some convertibles which can be fixed for a fraction of the cost a dealer will charge and ways to prevent them needing repairs with some simple maintenance.

Elliot Beardshall’s company CarHoods Northern has been fixing convertibles since 1992, and has seen it all. He tells us: “They have a reputation for being unreliable, but if you think of all the moving parts in a folding roof, they don’t go wrong as much as you might expect. But when they do need fixing, most mechanics won’t touch it. So people think you need to go to a main dealer and they will charge you £180 just to plug it in and see the fault. Then they’ll be wary of taking the mechanism to pieces so will want to replace the whole roof, which could be £10,000.”

A lot of the work Elliot gets is from insurance companies who want to avoid these big costs, as even the smallest mistake can write off your otherwise perfect convertible. He explains: “Most modern soft tops have the rear window integrated into the fabric of the roof, and it can be vulnerable. I do about two MINIs a week – someone will throw something like a tin of biscuits onto the rear parcel shelf and then forget about it. They then put the roof down and it smashes the back window.”

The rear glass is also a problem for certain Volkswagen and Audi cars, says Elliot: “The bonding for the window can fail after seven years. It will just fall out one day. You’ll come back and find the glass sitting on your back shelf! Obviously people will try and repair it, but it doesn’t really work and is just a temporary fix which might last a year or two if you’re lucky. You can always tell if they’ve tried it as the glue or sealant is always messy. Look for neatness if you are buying one.”

There are some other cars Elliot would steer clear of too, including the 2012-2020 BMW 4 Series, which he says “had leaks from the factory and even BMW can’t fix them.” Volkswagen’s Eos also has problems with its numerous electric motors and hydraulics, he says, which have to work together in harmony – but often don’t. “You see them for sale for £500 and it will drive fine, but the roof won’t work and it’ll cost a fortune to fix. It’s a real shame.

These cars have various sensors and they all have to give the all clear before the roof will operate. If one of them isn’t working then the system won’t allow the process to start. On some cars it means the boot won’t open either, which makes it difficult to get to the mechanisms and fix it.

The simplest roofs are those used on two seat roadsters. Elliot says the Mazda MX-5’s fabric roof is trouble-free and a replacement costs around £1,500 fitted – among the cheapest. The folding hardtop version of this car is reliable too. Honda S2000s also get his approval, and the Mk2 and Mk3 MINI cabrios are generally good news too. He says: “They learned the lessons on the first MINI convertibles and they are now great. The build quality on the new Mercedes drop-tops is unreal too.”

What to do if your roof goes wrong

The first thing to check is that everything is in the right place. Is the boot shut? If there is a ‘bag’ in the boot where the hood folds, is it locked in place? Is there anything else blocking the mechanism? Often there will be a warning light or message which will help you.

If everything looks good, then the next stage is to check the fuses. If they look OK then you might need to resort to emergency measures. These will allow you to operate powered roofs manually by following a procedure which might involve special tools you’ll find in the car’s boot. The instructions will be in the owner’s manual, or there will usually be a description online. These will normally only allow you to raise the roof though, and are not meant to be used as a substitute for getting it fixed.

If the car is out of warranty, then try looking for advice from owners’ forums to see if others have had similar problems. If it isn’t something you are able to fix, then look online for a specialist who will be able to help. Many, like Elliot, offer a mobile service.

Looking after your convertible car roof

There are easy measures you can take to keep your roof in tip-top condition. Elliot says simple cleaning and a bit of lubrication will save you a fortune in the long run. He gives the example of Bentley Continental GTCs: “These cars are now affordable to buy, so they are now in the hands of people who will leave them outside rather than putting them in a garage. That means they are exposed to the elements for the first time and they go downhill quickly. A replacement is around £5,000.”

The worst thing you can do, he says, is leave a soft-top parked under a tree: “The sap and bird droppings are what will make your hood look dirty and will encourage mould growth. Then the leaves and other stuff from the tree will block up the drain holes and you’ll get water finding its way into the car. That can cause big trouble with electrics and damage to the trim. If you must leave your car out in the open, get a cover to protect it.”

Even if you manage to avoid the trees, you will want to try and clean the roof twice a year. “Ideally, you want to be doing it once in the spring before you start using it and again in the autumn when you are not likely to use it again for a few months.”

There are dedicated fabric hood cleaners, but they vary in quality, says Elliot. Chemicals designed for tents and other fabrics can discolour the roof and “leave it feeling like sandpaper” with a coating which will crack. Some simple car shampoo and a soft nail brush will usually do the job, or even a pressure washer if it is used at a distance and at a lower pressure to prevent it damaging the fabric or leaving clean ‘scribbles’ on the surface when it is dry.

It will be tricky to see if the dirt and mould has gone while the roof is wet, so take a picture of the dry hood before you start cleaning so you know where to concentrate your cleaning efforts.

While you are cleaning, check the drain holes are clear too and then add a little white grease to the joints and locking points. Treat the seals to a clean too, and keep them lubricated with a special rubber oil or even Vaseline, says Elliot.

Are convertibles much cheaper to buy in winter?

Yes, as we are impulsive creatures. Clive Wilson, valuations editor at the industry’s valuation specialists CAP hpi, said: “Convertibles tend to go up in value from February to July, then stabilise and drop as you head into September and the winter months. Wholesalers are wise to this pattern and therefore tend to hold stock back during the winter months to maximise the seasonal effect and sometimes have dedicated sales during the spring and summer months to take maximum advantage.”

On higher value cars such as a Mercedes AMG C-Class Cabriolet worth £30,000, the seasonal uplift is around £1,500, according to CAP’s figures.

Should I buy a convertible?

This all sounds like hassle. Should you buy a convertible? Absolutely, if it is something you will enjoy. They do involve compromises and are not ideal for driving in cities where you are exposed and surrounded by fumes, and motorway driving is not much fun either. But if your journeys involve country lanes they are great fun and bring an extra element to driving.

There are also some bargains to be found if you know how to fix a convertible which needs a little attention or are willing to put up with a bit of shabbiness.

Wayne Lamport from classic car dealer Stone Cold Classics said: “If you are happy to buy a £1,000 convertible and run it into the ground then you can have a lot of fun. But if you want to keep one then buy the best you can afford as by the time you’ve sorted out problems with the roof and rust then you’ll probably have spent more than buying a good car in the first place. There are plenty around so just wait until the right car comes along.”

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