Car clinic: night-time speed cameras, second-hand VW, scratched windscreens and Citroën ignition problems

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.

INSPECTOR GADGET
Dave Pollard has written several Haynes manuals and has tested just about every car-related accessory.

LADY DRIVER
Emma Smith is a journalist specialising in consumer issues and is a regular Driving contributor

THE DEALER
Jason Dawe is our used car expert and has appeared on Top Gear and The Morning Show.

Q. Driving on the M1 at restricted speed through roadworks the other night, I began wondering whether average-speed cameras still function in the dark. Can you enlighten me?

TP, Bradford

A. Average-speed cameras use automatic numberplate recognition (ANPR) to log when a car enters and exits a monitored section. The system can then calculate a vehicle’s average speed between any two cameras to discover whether it has exceeded the limit.

To answer your question: yes, they can see in the dark. Each unit illuminates the road ahead in infrared light, invisible to the eye but not to the camera’s sensor, so that numberplates can be captured even in the dead of night. Contrary to popular belief, motorcycles with their single rear numberplate don’t escape detection either. According to Vysionics, the company that makes the cameras: “The cameras can be operated as either rear or forward-facing. Some of the cameras on the M1 currently are operating in rear-facing mode, which allows them to read motorcycle plates.”

Average-speed cameras are rare on motorways, except where there are roadworks. The company calculates that on average, one fine is issued for every 10,000 vehicles passing through a section of roadworks.

ES

Q. For the first time in 20 years I am without a company car. I am thinking of buying a two-year-old Volkswagen Phaeton with 6,500 miles on the clock for £25,000. Does that sound like a good deal? And if I do buy it, should I then take it to VW for a once-over?

NJ, Hull

A. Assuming you are looking at an 11-plate 3.0 TDI 4Motion (and not one of the long wheelbase models, which fetch about £1,500 more), your figure of £25,000 is a little high. A figure closer to £23,000 is more in line with market prices. That said, at less than half the cost of the car when new, either price will buy you a huge amount of car for the money.

The Phaeton does not have the cachet of similar cars from Audi, BMW and Mercedes-Benz but it is just as good to drive, travel in and live with as any rival.

A new Phaeton comes with a three-year/60,000-mile warranty, so your car should be covered for another year. However, for that warranty to be intact, the car will have to have been serviced in accordance with the manufacturer’s recommendations, so check with a VW dealer before you buy. Regardless of the servicing schedule, for peace of mind it is still worth having the car checked by a Volkswagen dealer after you buy. You might also want to consider extending the original new-car warranty with a VW used-car warranty (about £900 for an extra year, including RAC breakdown cover).

JD

Q. There are some nasty scratches on the windscreen and driver’s side window of my Audi A3. Could they be polished out? I asked a windscreen repair man but he was unable to help.

RW, Banwell, Somerset

A. To get a clear picture of the damage, clean your windows thoroughly. While you do this, make sure the wiper blades are free of debris, because abrasive damage from the blades could have caused the problem on the windscreen in the first place. Scratches on a windscreen can be repaired — within limits. It’s not worth attempting if the screen is seriously pock-marked, because it would probably need replacing soon anyway. And there is a limit to the depth of scratches that can be repaired.

The unscientific way to check if a repair is possible is to drag your fingernails gently down the screen. If a fingernail snags so badly that it stops dead, the odds are that a repair will not be possible.

Most comprehensive car insurance policies will reimburse the full cost of a repair without requiring you to pay an excess or affecting your no-claims discount. Check your policy to confirm this. Repairs would typically be in the range of £50-£120, depending on the damage and the size of the screen. For side windows, simple replacement is usually more economical.

DP

Q. My daughter’s Citroën Xsara Picasso started fine during the summer but now the mornings are getting colder, it’s proving harder to get going. We replaced the battery and glow plugs and checked the ignition fuses but the problem remains. What next?

AB, Basildon, Essex

I fear you have paid for unnecessary new parts because the fault most likely lies with the car’s electrical system, which is affecting the battery’s charge. The problem is showing up now only because cold starts demand a well-charged battery. Oil is thicker when cold, so the starter motor needs more energy from the battery to turn and start the engine, and the glow plug heaters must be on for longer to achieve the required temperature. I suspect the battery is retaining enough charge to start the car when it’s warm, but not enough for when it’s cold.

The most common reasons for this are a faulty alternator (which is failing to charge the battery properly as you drive) or a constant current drain (energy leaking from the battery, even when everything is supposed to be switched off).

To check the alternator, try this simple test. Start the engine, let it idle and then turn on the headlights, fog lights and heated rear window. Now set the heater fan to maximum. Listen to the note of the heater fan and then rev the engine to about 2000rpm. If the alternator is working properly, you will hear the fan speed up as the voltage rises. If it doesn’t, get it checked by an auto electrician. If the alternator is ruled out, consider a current drain. An interior light that refuses to turn off or a jammed relay (an electrically operated switch) is a typical cause. Find a garage that will work through the possible diagnoses logically and thoroughly before asking you to fork out for new parts.

TS

Got a car problem?

Email your question to carclinic@sunday-times.co.uk, 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.