Expert answer

Hi Anne,

There are loads of different reasons why a stop-start system won't work as you might expect it to. Most of the time it's down to the condition of the battery or the drain on it, though it could be due to the ambient temperature, too. Here are a couple of items on the site to read through before you consider having the car looked at:

Why won't my car's stop-start system work?

Why does my stop-start not always work?

Expert answer

Hi Roseanna,

First things first — if you’re doing mostly urban and motorway miles, you really don’t need an SUV. A more conventional hatchback, saloon, or estate is going to be more comfortable, better value, more economical and a better-engineered vehicle all round. If you’re looking for something with practicality then the likes of a Skoda Octavia Combi estate, a Volkswagen Golf Estate, a Kia Ceed SW, or the new Ford Focus Estate all have much bigger boots than any small-to-medium SUV (more than 600 litres, all of them, compared to around 450 litres for, say, a Nissan Qashqai), and they’re all better to drive and more frugal.

However, if you’re hooked on SUVs then we’d recommend a SEAT Ateca (plain wrapper, but it’s roomy, comfy and nice to drive) or a Toyota C-HR (small on the inside, relatively, but hugely stylish and the hybrid version is frugal). If you’re looking to ‘posh-up’ a bit, then the incoming new Audi Q3 is a bit of a stunner, or if you want something smaller and more affordable than any of those, try the updated Fiat 500X, which is kinda cute and charming.

Here are our relevant reviews for you to read more:

Skoda Octavia Combi review

Volkswagen Golf Estate review

Kia Ceed Sportswagon review

Ford Focus Estate review

Nissan Qashqai reviews

SEAT Ateca reviews

Toyota C-HR reviews

Audi Q3 reviews

Fiat 500X reviews

Expert answer

Hi Janie,

On the parking sensor issue, it just seems to be a bit of a quirk with the Audi Q7 that to get the front sensors on when moving forwards, you have to press the parking sensor switch, although they do, as you point out, come on automatically when you select reverse. We’re not sure why this is, but it might be worth a visit to your dealer to see if there’s some finicky bit of software code that can be re-set to activate them automatically at low speeds.

As for the stop-start system, if could be a few things. Obviously, there may be a fault, in which case get the car booked into your dealer for a check-up. Or it could be that you’re doing a lot of low-mileage, short runs, which aren’t allowing the engine and other systems to get fully up to temperature. Stop-start isn’t a simple on/off system — it’s controlled by the engine management and that won’t let stop-start activate if it thinks that the engine hasn’t warmed up enough (stopping and starting a cold engine can be damaging) or if it has detected that you have a lot of high-energy drain systems (air conditioning, demisters etc) running. Try and analyse your driving the next time you go out and see if any of this fits. If not, head for your dealer. 

Expert answer

Hi Aisling,

Our information would agree with what you were told, that the recommended interval is indeed 210,000km, regardless of time. Remember: treat that as a maximum, not a minimum...

Expert answer

Hi Hugh,

Prices for changing the belt will vary depending on the garage you bring the car to and whether they use genuine Audi parts, so best thing to do is shop around. I can tell you that, assuming you have a 2.0-litre TDI diesel model, the work should take no longer than three hours.

Expert answer

Hi Colin,

There are well-documented issues with stretching VAG timing chains, unfortunately, and yes, it's very expensive to replace a chain. The problem is usually identified by a distinctive rattling on cold start-up before it manifests itself in engine running issues and there are also chain inspection ports on these engines so, if a car you're looking at has had proper maintenance, you can have the chain inspected.

Expert answer

Hi Anthony,

You should be fine, actually. Your 3 Series should (emphasis on SHOULD) be worth around €22-25,000 as a trade-in, and a 171 4 Series Gran Coupe starts at around €30,000-ish, so adding €10k of change-up budget should put you in the right ballpark. Ditto the A5 Sportback, although you will find examples of both on a 171 starting with a €4 rather than a €3… Shopping around a bit should do the trick, though. Both cars are excellent choices, and go for the Audi if you want maximum reliability.  

Expert answer

Hi Tracy,

I'm afraid without knowing exactly which car you have, this is impossible to diagnose. You should bring the car to a good mechanic or auto-electrician.

There are many reasons for a stop-start system to not always work. Read this question and answer on that subject for instance.

Expert answer

Hi Stephen,

The timing belt needs to be replaced every 210,000 kilometres, regardless of time. The cabin filter needs replacing every 60,000km/24 months, but there is no set service interval for the air conditioning system itself.

Expert answer

Hi Stuart,

Not for some time yet. The recommended minimum change period is every 210,000 kilometres, regardless of time.