Johannesburg - City Press motor expert Justus Visagie, with some help from car engineer Martin Pretorius, provides useful answers to your automotive questions.
Best value for money luxury car?
Kgomotso Tsomele: "I drive a 2014 BMW 520d as a family car. I'd like to trade it in for a 2016 model of one the following: Audi A7, Audi A8, Mercedes-Benz CLS 250 CDi or a BMW 7 Series. Which car will offer the best value for money, better fuel consumption and an excellent future trade-in?"
Justus and Martin: "None of the replacements that you mention will maintain good value – expensive cars depreciate terribly. The new Audi A8 is on hand, with a new A7 hot on its heels, so the current models will lose more money than the relatively fresh 7 Series. The same goes for the Mercedes-Benz CLS (which is a less practical family car, anyway), but it will probably be the lightest on fuel, with its engine being a 4-cylinder. The 7 Series makes the most sense financially, but the Audi A7 Bi-TDi is a masterpiece."
Tebogo Monnaemang: "I drive a 2013 Chevrolet Captiva that I bought new. It has driven 89 000km but I have extended the service plan. Is it a good idea to change it, now that Chevrolet is leaving the country?"
Justus and Martin: "Your Captiva is still fairly new, and Chevrolet (and its representatives) will be around to honour your service plan long after it's expired – probably long after you would have sold the car anyway.
"Spare parts also won't become a problem for at least the next five years. You're already looking at a resale value drop as a result of Chevrolet's exit (Isuzu and Opel stay), so you might as well get some value out of the car. Relax, sit back in that Captiva's comfortable seats, and enjoy what is still a very good car, even if it's an orphan."
Batloung: "I have a 2005 VW Polo 1.9 TDi and it has a problem with its number one injector. The mechanic tells me all four injectors will have to be reconditioned. I don't understand why I should repair injectors that are not damaged."
Justus and Martin: "Diesel injectors lead a very hard life, facing tremendous heat and pressure, along with severe vibrations and questionable fuel quality. Therefore, injectors count as wear items on most (if not all) modern diesel engines.
"The problem you're experiencing is only the first indication of those injectors reaching the end of their usable life – whatever's wrong with that one will most likely happen to the others very soon. Seeing as there's a lot of labour involved to replace (or recondition) one injector, it's prudent to extend the work to the others while the engine is opened up.
Richard Stevens: "I drive a 2005 Ford Fiesta 1.6 Trend. Are there any modifications I could make to reduce fuel consumption? What car do you recommend for Uber driving? It has to be a 2012 sedan."
Justus and Martin: 'Your Fiesta has a fairly advanced engine management system, so it runs very close to its peak efficiency already. Your best bet would be to improve gas flow into and out of the engine by fitting a more efficient air filter and freer-flowing exhaust system.
"As for your Uber inquiry, you probably can't do better than a Toyota Corolla or a Corolla Quest. Also consider a Nissan Sentra of 2014-ish vintage – they're strong, spacious, cheap to run and comfortable."