Most gas has enough ethanol to act as gas-line antifreeze

Q: Since gasoline is now required to contain ethanol, is it no longer necessary for me to add gas-line antifreeze in winter?

A: Gasoline sold in Ontario is required to have an overall ethanol content of five per cent. But, as not all engines can tolerate it, you'll typically find 10 per cent ethanol in regular gas, five per cent in mid-grade, and none in premium grades.

Extra gas-line antifreeze agents generally shouldn't be necessary for most regular and mid-grade users except, perhaps, in extreme conditions. Premium gas users should consult their owner's manual for recommendations on gas additives.

Before the government ethanol requirement took effect, many major oil refiners sold gas without ethanol during the winter, stating it was unnecessary – although they've always been more than happy to sell it to you in those little bottles.

Keeping your tank more than half-full in winter helps minimize condensation and avert potential problems.

Q: My husband says I shouldn't turn on the car heater for 20 minutes after first starting up on a cold winter day, in order to help the engine warm up and save gas. Is there any merit to this claim?

A: On the first cold start of the day, the motor oil is cold (making it denser), available battery power is lower due to temperature, and computerized systems that optimize fuel efficiency may not yet be online until the sensors have warmed to operating temperature.

For the first 10 to 20 minutes after cold start-up, the engine is typically running under "minimum operating conditions" and a lot of unburned fuel may go down the tailpipe. Technically, it would help the engine reach its optimum operating temperature faster if you didn't turn on the interior car heater during this time.

Most newer autos typically provide interior heat fairly quickly after starting (within five minutes), but if yours takes a while, you might consider using a portable electric car heater that plugs into the car's accessory outlet to bridge the gap.

Engines warm up best by driving, so warming up by idling for extended periods after starting is discouraged and may be illegal, as it is in Toronto.

Email your non-mechanical questions

to Eric Lai at wheels@thestar.ca.

Personal replies cannot be provided.