The car clinic experts
TIM’LL FIX IT
Tim Shallcross used to train AA patrols to ﬁx cars. Now he advises the Institute of Advanced Motorists.
Jason Dawe is our used-car expert and has appeared on Top Gear and the Morning Show
Q. Since I stopped making a daily commute on the motorway four weeks ago the diesel particulate filter warning light has twice appeared on the dashboard of my 2011 Range Rover 4.4 TDV8 Vogue. Each time that it happened I’ve made a dash for the nearest dual carriageway to burn off the soot and clear the filter, as recommended in the car’s handbook. My wife does even shorter runs than me in her diesel hatchback, but has had no such problems. Is there anything I can do to stop a recurrence?
BT, Monifieth, Angus
A. Soot collects on the diesel particulate filter (DPF) and needs to be burnt off from time to time to stop it clogging up. For most drivers this will happen automatically with regular runs on a motorway or dual carriageway, but for some motorists it will require a special trip. It usually takes a 20-minute run at about 70mph to burn off all the soot, but the main thing is that the engine speed remains at 2500rpm or more for the duration.
Because your Range Rover’s powerful engine does not have to work or rev very hard on the short, low-speed journeys you are now making, this may be something you have to learn to live with. (Your wife’s diesel hatchback does not have the same problem because its smaller engine has to work harder on the same journeys.)
However, it is worth checking a couple of things to make sure your engine is as soot-free as possible. Before DPFs, a good sign of an engine running inefficiently was black smoke coming from the exhaust, but the DPF now absorbs this, which may mask a problem such as a worn injector, or low fuel-injection pressure. Ask your dealer to check for any fault codes stored in the car’s computer memory.
Using the wrong engine oil or not changing it often enough can also cause problems. For your Range Rover a garage should use a 5W-30 grade oil with the Ford specification WSS-M2C934-B (a hangover from when Ford owned Land Rover). The 5W-30 refers to the oil’s thickness when cold and hot, while the Ford specification indicates that, among other properties, it is a low-ash oil (meaning it is less likely to block the DPF).
For topping up, Land Rover recommends Castrol SLX Professional Powerflow C1 5W-30. If you buy a different brand, make sure it has the same 5W-30 viscosity and that it also meets the Ford specification. Your wife’s car will need a different oil for top-ups.
Q. Driving home recently I heard a clunk from under my 10-year-old Toyota Land Cruiser. Pulling over, I found that the front offside wheel had worked loose because all the retention bolts had broken off. (The wheel had been fitted with a new tyre after a puncture a year ago, and the car has not long passed its MoT test.) What has gone wrong?
A. Loose, missing or over-tightened retention bolts are the prime suspects. Check for rust or corrosion on the inside of the wheel: if part of it has crumbled away, the bolts could have become loose. If one or more of them has sheared (basically, sliced off), this would suggest over-tightening. It might be that just one or two bolts were loose or badly adjusted, causing them to shear, break or drop off, which then left the other bolts under too much stress to support the wheel for long.
If any of the wheel bolts were loose or missing, the car would have failed the MoT. The tester should also have checked the bolt holes to make sure they were not worn or elongated. This is only a visual test, so is not foolproof, but most likely the problem occurred after the test.
Whatever the cause, it is important to check that none of the other wheels is corroded, and have the bolts tightened to the correct torque. Ask a garage to adjust them using a torque wrench, which can be set to a specific tightness. If the wheel holes are worn, you will need to change those wheels.
In future, check the bolts regularly to make sure they are still tight. Many commercial vehicles have wheel-nut indicators: yellow or red pointers attached to the nuts so the driver can see if one has turned. These will not usually fit on a car but you can adopt the same principle by making a small mark on the bolts and wheel with an indelible pen or paint, then periodically checking to see if the marks remain aligned.
Q. I spotted an attractive SUV parked near my house and was surprised to discover that it was a Dacia Duster. I’m not really aware of the brand, although I’ve seen its cars frequently on the Continent. Are they widely available in the UK? OD, London
A. Dacia may be unrecognised by many British buyers but the company has been around since 1966 when it was founded in Romania under the original name of Uzina de Autoturisme Pitesti. In 1999 it was bought by Renault with the intention of building Dacia as a “value” brand in central and eastern Europe, but interest was so strong in western Europe that the parent company decided to launch the brand further afield.
By 2010 Dacia was selling more than 350,000 new vehicles a year worldwide and in 2011 it became the fifth-bestselling passenger car brand in France. It has been the fastest-growing car maker in Europe for eight years in a row, and finally reached the UK in January. You can now buy Dacias at about 150 Renault showrooms in Britain, and the marque has a handful of standalone dealerships too (see dacia.co.uk for details).
It offers four models in the UK: the Duster SUV (pictured, top), Sandero supermini, Sandero Stepway (a supermini with SUV styling) and Logan MCV estate. All have remarkably low starting prices. The Duster, for example, costs from £8,995 for the entry-level two-wheel-drive version, compared with £17,495 for the basic front-wheel-drive Kia Sportage. The Sandero, meanwhile, starts from £5,995, compared with £10,795 for an entry-level Renault Clio.
The latest cars have been engineered and designed to compete with western European brands, although they are definitely pared back in terms of luxuries and styling. Using Renault technology and platform engineering keeps development costs to an absolute minimum, and having factories in Romania, Morocco and India keeps production costs low.
All Dacias come with a three-year/60,000-mile warranty. Don’t expect a discount on any of these models, however.
Got a car problem?
Email your question to email@example.com, or write to Car Clinic, Driving, The Sunday Times, 3 Thomas More Square, London E98 1ST, with a daytime phone number, your address and as much detail about your car as possible. We can’t reply personally, so please don’t send original documents or SAEs. Advice is offered without legal responsibility.
Published on September 15, 2013