My car's mileage leaves me cold in the winter

I have 2012 Toyota Camry Hybrid XLE that used to go for 1,050 kilometres on a full tank (60 litres) in the summer. However, in winter, it only travels 650-700 kilometres. A mechanic couldn't find anything wrong. I know that mileage drops in winter, but this much? – Suyash

You can expect to use 20-25 per cent more fuel in winter, if driving short distances. The primary reason is that the engine requires a richer mixture to start and uses more fuel than normal while warming up. The added load of the heating and electrical equipment – rear defrost, seat heaters, headlights (more driving in the dark) – adds to the load placed on the engine. It has been a harsh winter wherever you live in Canada, so I would wait until things warm up before assuming there is anything wrong.

Dual Shaft Gearbox

I bought a new Volkswagen Golf TDI station wagon and it has a dual shaft gearbox (DSG) transmission. It has a clutch like a motorcycle in that the clutch is a multi-plate clutch in a fluid bath. VW recommends replacement after 60,000 kilometres. Is this reasonable in Toronto stop-and-go traffic? Should the fluid be replaced more often? Also, in stop-and-go traffic, would you recommend keeping the transmission in the regular driving mode (upshifts at 2,000 rpm)? – Alex

Great transmission, one of my favourites. Essentially, the DSG consists of two clutch packs running simultaneously on two shafts. One shaft operates gears 1, 3, and 5 (as well as reverse). The other drives gears 2, 4, and 6. The compact design involves a pair of smaller multiplate clutches operating in an oil bath instead of one large one. I recommend following VW's recommended fluid change intervals, which take into account city driving. Again, follow the manufacturer's advice – leave it in drive. It was designed, developed and tested – and is warranted – based on "normal" use.

What car?

My wife's car (2005 Cadillac CTS) was written off. She's not sure if she should get a 2010 Lexus ES350, 2010 Volkswagen CC or a new Toyota Matrix. I suggested she lease a car instead of financing but she does not see the value of leasing. Appreciate your advice. – Bill

Leasing makes sense if you can write off some of the added cost or are willing to pay extra to simply turn it in and get a new set of keys every few years. As to your list of candidates, that is a real apples versus elephants comparison. The Lexus, and to a lesser extent, the VW would provide her with a level of luxury, features etc. she was accustomed to – but in a newer car. The Matrix would be an ultra-reliable and sensible new car – but not what she has been accustomed to.

Engine oil

Is it true that some provinces have made it mandatory for engine oil manufactures to have one-third of synthetic oil as part of the total engine oil component? If it is indeed true, can you provide me with more information? And is it also fair to say that oil leftovers from restaurants (from deep fryers) can be converted into synthetic oil via the purifying process? – Neil

There is no provincial regulation regarding engine oil requirements other than those related to disposal and the environment. As for the oil leftover from restaurants, that may in fact be possible as a minor component in lubrication oil, but it's not feasible. There is a great deal of chemistry involved in developing and manufacturing engine oil and a massive amount of testing, verification and certification. Oil is more than a slippery substance, it is a cleaner, a coolant and a plays a role in emissions as well. You might be referring to attempts to use vegetable oil as fuel for a diesel engine. This has been done in some cases but is certainly not something I would recommend – the costs of failure are too high.

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