Q: Purchased a new 2020 Audi A4. Salesperson wanted me to buy a maintenance plan that would cover oil changes for four years. Can my local mechanic handle the changes? Is there a reason I would need to use the dealer?
L.S., Davie, Fla.
A: Your warranty will not be voided if you chose to have oil changes, or any routine service, done by your local mechanic. You may even do the jobs yourself. All you need do is save the invoices and receipts as proof.
Q: I have two direct injection vehicles. When I get down to 3/4 tank I fill up. Does this mean I always have mostly really old gas in the tanks?
A.A., Alsip, Ill.
A: You do not have mostly old gas in the tank. You are regularly freshening it with new gas. If you sip half a glass of beer and then top it off with some cold brew, the older stuff does not sit on the bottom of the glass.
Q: I enjoy reading your column in the Hartford Courant. In a recent column, "B.K." of Henderson, Nevada, asked about the coolant temperature in his 2005 Corvette. You replied that water boils at 212 degrees, or 226 with a 50/50 antifreeze mixture. Those would be the boiling points at sea level pressure. Most, if not all, engines have pressurized cooling systems that allow water to reach higher temperatures than that without boiling. This is why you shouldn't remove the radiator cap from a hot engine. If any of the water in the engine is above the sea level boiling point and you release the pressure in the system, that water will immediately boil to steam and blast scalding coolant all over you.
G.G., West Hartford, Conn.
A: You are absolutely right. Are you also a mechanic?
Q: I got my car in 2018 from a dealer in the San Diego area where I lived at the time. It was a "loss leader " sale. The car is in impeccable shape and I want to keep it that way. I conditioned the convertible top with a waterproof product. I'd like to know how often that is necessary. Also can you advise how I can best maintain the inner parts of the car's convertible roof such as the rubber seals? Car is garaged in the winter.