Expert answer

Hi Ian,

If nothing else, you need to adhere to manufacturer servicing schedules to ensure you don't invalidate your warranty. If you don't trust your local dealer then contact Opel directly, though these figures should be in your owner manual as well.

Besides all of that, we'd thoroughly recommend servicing modern diesel cars regularly, as the car makers often push the service intervals out to appeal to fleet buyers. Regular oil changes in particular are a very good idea.

Hope that helps

Expert answer

Hi Tony,

OK, there are a couple of issues here. One is that a trawl of the Internet forums, especially in the UK, seems to indicate that there is a common problem on the N47 2.0-litre diesel engine whereby the timing chain can either fail or jump its sprockets. Either way, you're looking at an engine failure and a need for replacement. Not a trivial matter. 

However, BMW has not issued a recall or any specific advice in this area, which may indicate that there has not been a significant level of these incidents. It's easy to accuse a car company of ignoring a major problem but actually that's rarer than you'd think and it's all to easy to get into a froth of indignation from just reading complaints on the internet.

That being the case, we'd simply advise caution. There are some very good independent BMW specialists out there (such as http://www.bloomfieldgarage.ie/) and it might be worth getting in touch with them for more detailed advice.

Also, insist on full service history with these cars, paying particular attention to oil change intervals.

Expert answer

Hi Dawn,

Going on personal experience, I'd say that the C4 Picasso would be the most economical of the bunch. All of them should be able to get between 45-50mpg, and I'd say the C4 should just nudge above 50mpg. That said, you have to remember that what dictates fuel economy more than the car is your driving style. Practice driving with light throttle openings, anticipating further ahead and always using gentle control inputs and you should be able to get that economy figure improved. Also, take any excess weight out of the car, make sure the engine is serviced regularly and the oil changed often and get a good set of low-rolling resistance tyres, and keep them at the right pressure. It all helps.

Expert answer

Hi Eddie,

You've not told us what engine you mean, so here's a list of the most common engines. Note that timing chains don't have a change interval and they should last the life of the engine if scheduled oil changes are carried out and all else is well.

 - 1.2-litre petrol: timing chain
 - 1.3-litre CDTi diesel: timing chain
 - 1.4-litre petrol: timing chain
 - 1.6-litre petrol (both turbo and NA): timing belt - change every 150,000km or 10 years
 - 1.7-litre CDTi diesel: timing belt - change every 150,000km or 10 years
 - 1.8-litre petrol 125hp: timing belt - change every 90,000km or six years
 - 1.8-litre petrol 140hp: timing belt - change every 150,000km or 10 years
 - 1.9-litre CDTi diesel: timing belt - change every 150,000km or 10 years

Expert answer

Hi James,

As discussed via email:

That generation Audi A6 is in general a reliable car, but not fault-free. Some owners have had no problems, while others have been plagued. The Multitronic transmission is not renowned for being the most trouble-free, though units made pre-2006 have the most problems. Also, the gearbox's fluid should be changed at 55,000 and 115,000 kilometres (or 35,000 and 75,000 miles) so the car you're looking at should have had two changes by now. Check that it has and then look in detail at how the gearbox works. Does the 'PRNDS' indicator on the dash flash? Is there hesitation? Is it easy to get reverse?

No matter what turbodiesel car you look at you'll hear of turbo problems from some owners. Most of the time it's likely to be due to poor oil maintenance. So check the car's service history in terms of oil changes and that the oil level itself is right. They do use a bit of oil.

While you're checking out the car in detail, make sure the air conditioning can produce freezing air in just a few minutes, as these have been known to fail.

I'm probably making this sound worse than it is! I'd buy an A6 for myself - it's a good car - you just need to know what you're looking for and not get caught out by one of the few badly maintained examples out there.

Let us know how you get on.

Expert answer

Hi Jackie,

We would expect a car's brakes to be thoroughly checked during a service for sure, though whether they warrant changing really is up to the mechanic doing the job. As that noise was not there when you bought the car it's fair to assume there was no issue with the brakes then - though clearly the pads didn't have much left on them. It's good that they're doing it now for you, even if the person you are dealing with is dismissive.

It's quite poor that the mechanic wouldn't find out what the code 82 was about, but there you go. The Insignia's engine management system monitors several parameters such as number of cold starts and engine speed and calculates when you need an oil change. If you use your car more frequent short journeys rather than longer ones then it may require changing earlier. Many people ignore this read out and just change their oil according to mileage or time, but the official word is to stick to what the engine management computer says. Just make sure the garage resets it again for you.

Last point: I wouldn't expect the garage to pay for this oil service. If they do, it's a bonus!

Hope that all helps put your mind at ease.

Expert answer

We checked with Mark from www.micksgarage.ie and he told us, "One of the guys here has worked as a service advisor and warranty manager in the past and can confirm that if you buy genuine service parts and service the car yourself, the warranty is unaffected. Also, for those looking to undertake the jobs themselves, the Haynes website has some useful videos on oil changes, filter changes and spark plugs etc."