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Hi Gerry,

You've picked three difficult cars to choose between. Obviously, both the Hyundai and Kia are essentially the same car beneath the skin, and both come with temptingly low prices and long, long warranties. The SEAT's three-year warranty looks a bit brief in comparison, but then you are buying into a car with excellent reliability and high quality, so there's that.

You've also got an odd combination of relatively high mileage, but in an urban location, which suggests that you won't be working up enough speed to generate exhaust heat to keep a diesel particulate filter (DPF) clean. With all that in mind, I think your best best might be a Leon 1.2 TSI petrol. It's a cracking engine, nearly as good as a diesel on fuel economy, but with no nasty surprises waiting in the exhaust. Both the Hyundai and Kia are excellent cars, but both are best experienced as diesels.

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Hi John,

OK, there's a balancing act to be done here. There's no doubt that the CO₂-driven diesel stampede since 2008 has driven up the values of second hand diesel cars and driven down the values of their petrol equivalents. However, that is starting to change, and cannier buyers (helped in some part by investigations and comparisons by the CompleteCar.ie team - blowing our own trumpet etc. etc.) have shown that the overall cost of buying and running a petrol engined car can actually be lower than that of a diesel, especially for those drivers on relatively low mileage like yourself.

In that sense, I'd be well in favour of getting the petrol one, but there is a caveat to that - the A4 is very much a business market car, and therefore most of its prospective buyers, new and used, will be expecting to see a TDI badge on the boot. If you're buying on a lease or a PCP with a guaranteed future value, then that's not such an issue, but the answer is yes, you could well lose out a little on depreciation over a few years. Probably not a lot, but it's a moving target at the best of times.

Can I suggest this? Instead of an A4, have a look at the A3 Saloon. It's admittedly smaller, but it is also prettier, better to drive and good enough to win Family Car of the Year from the Association of Professional Motoring Press (APMP). It can also be had with the excellent little 150hp 1.4-litre turbo petrol engine and should be somewhat less sensitive to the diesel/petrol tug of war when it comes to second hand values.

Let us know which way you go anyway.

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Hi Eoin,

Yes, it's a fine purchase as long as you go in with your wits about you and make sure that it's got a full service history. Any expensive German car without one is effectively worthless... That generation 3 Series was pretty robustly built and was less technically complex than later versions, so there's less to go wrong.

If it's the 2.5 straight-six petrol you're looking at, then it's a reliable unit, and well-proven, but watch carefully for any signs of water leaks or head gasket trouble. If it's had cooling or head trouble in the past, it's very likely to happen again and you could be looking at an engine swap. If it's the 2.5 diesel you're looking at, check for any white smoke from the exhaust or lumpy power delivery, which could indicate turbo problems.

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Hi Maria,

I presume you're talking about a first generation Mazda3, seeing as most of the second-gen models came with diesel power. The official economy for a 2005 model year Mazda3 1.6 petrol is 39mpg with CO₂ emissions of 172g/km.

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Hi Kevin,

Generally speaking it's the E-Class that followed, the 2002 onwards model, that gave all the trouble, and the generation you're looking at doesn't give quite so much bother. As far as we can gather, the E200 K should be a reasonably rugged engine, but the crucial thing to note is to make sure that it has been serviced on time every time, by someone who knows what they're doing, and that you continue to do so when you own it. If there's no service history, or a patchy one, walk away.

Also watch for rust bubbling up under the front wings and make sure that the front suspension bushes were replaced at 60,000 miles. In that generation of car, I wouldn't necessarily expect the diesel version to be any more or less reliable.

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Hi Kamal,

If you sell it privately, you'd probably get around €5,500 for it, maybe €5,000 for a trade-in.

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Hi Nelius,

Cracking car the original Mazda6. One of the best-to-drive saloons ever built and the good news is you're looking at mostly pros, and very few cons. The only real mechanical weak point is the clutch - we've heard of them failing at as little as 50,000km so check to make sure that the action is smooth and not too heavy and that the gear changes are crisp and quick. Any slipping or smell should set off alarm bells.

Other than that, there are a few recalls that you need to make sure were attended to (leaky fuel lines, dodgy fog lamps, brake warning light and oil seals) and it's worth checking to make sure that the suspension and steering are in good fettle and that there's a good set of high-quality tyres on the car; the better to enjoy that wonderful handling balance.

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Hi Paddy,

That's a tricky one to assess from afar I'm afraid as it could be several different things. The clutch cable/pedal/actuator could be faulty or out of adjustment, the gear linkage could be out of position or the gearbox itself could have major internal problems. The good news is that the latter is the least likely scenario.

I'd urge you to bring the car to a good mechanic to have a look at it for you before quoting for the fix.

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Hi Dylan,

Ok, there is a problem here. Modern water-based car paints can indeed be affected by the metallic contents of sun screen, and Volkswagen Group cars seem to be particularly vulnerable. The solution, at least in part, seems to be a full-body mechanical polish, although you could take your chances and have a go yourself with T-cut. It's unlikely to cure the problem entirely though, so the only viable option could well be a full respray.

Of course, if the car is younger than three years old it should be covered by Volkswagen's paint defect warranty. We've heard that Volkswagen (and other companies) won't honour paint warranties where sunscreen is concerned (because it's not strictly a manufacturing defect) but you could try and argue it out with them. Certainly, it seems obtuse to us to argue that reactions to something as common as sunscreen indicate a serious lack of quality control in the painting process.

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Hi Tina,

Well, it all depends on what kind of car you want. Trading in your old Golf and adding €7,000 probably gives you a budget of between €8-9k and that, thankfully, means the world is your motorised oyster.

 If you want to be sensible, you could just stick with what you know - there are plenty of 2008 Golf 1.9 TDI models around in your price range and there are few cars that are better to be honest. Plenty of Focus, Astra, Auris and Kia cee'd options around too if you fancy a change.