Q. My 2008 Toyota Matrix, with a standard transmission, gets worse mileage in the cold weather, down by about 5 miles per gallon. With more cold weather on the way, is there anything I can do to improve the mileage in winter? I was thinking of synthetic oil for starters.

A. In winter weather you can always expect a drop in fuel economy. This is due to the formulation of “winter” gasoline. It is not unusual to see up to a five percent drop in fuel economy due to this cold weather formulation. It is this special formulation that allows for easier starting as the temperatures dip. Add this to slightly longer warm-up times, lower tire pressure, and thicker fluids in the other components of the car; it is easy to see how mileage will be lower. That said it looks like you are seeing a 20 percent drop in fuel economy, which to me seems excessive. At this point, it would make sense to have an overall evaluation of the car and request a fuel mileage test. Although you won’t see a huge improvement, switching to synthetic oil may improve the mileage slightly as well as allowing easier starting in cold weather.

Q. I will be purchasing a certified pre-owned 2007 BMW 328xi with a mileage of 22,000. I have a question regarding the run-flat tires they come with. I've heard some nasty things about how run-flats wear out a lot faster than regular tires. Can you comment on this?

A. I have seen run-flat tires on some cars last as little as 12,000 miles. The various BMW forums seem to show that 20-25,000 miles is closer to an average. You could consider replacing the run flat tires with a conventional design, but you need to get over the fact you don’t have a spare tire in case of a flat tire. At the least I would carry a portable air compressor in case one of the tires is low on air.

Q.  Will antifreeze freeze if you don't add the right amount of water?

A. Typical ethylene glycol antifreeze, when mixed in a 50 percent ratio of water and antifreeze, will protect against freezing to 35 degrees below zero. Add more antifreeze and the protection point gets lower, but only up to 70 percent antifreeze. Over this percentage the mixtures loses it ability to protect against freezing. Straight antifreeze will freeze at seven degrees above zero.

Q. I have a 1989 Volvo 244 sedan with a cracked/leaking engine block. Is it possible to safely patch the leaks with JB Weld? I’m trying to get this car through one more winter.

A. A technician may be able to determine if the problem is a cracked block, leaking head gasket or cracked head. As far as patching the crack with a product like JB Weld, as good as this product is, it may provide only a temporary solution to an external crack. Considering the car is 20 years old, a used engine may be reasonable solution.

Q. The left blinker (directional) in my 2004 Dodge Caravan started to blink very fast. The right seems to be working normally. The bulbs seem to be working, just more rapidly. Is it the bulbs, fuse, or what?

A. Whenever turn signal bulbs blink rapidly it is usually an indication of a faulty bulb, socket, or in some cases a wiring problem. When checking the bulbs don’t overlook the small running light bulbs. In some cars if one of these bulbs is out, it will have the same effect you have described.

Q. Is VW delaying the release of the Passat and Passat wagon with the V6 and 4motion?  When I go to the VW website or any dealer sites, the only model they mention is the “Komfort,” which only has the 2.0 liter turbo 4-cylinder and no all-wheel drive. Do you have any information on these cars?

A. According to Steve Keyes, the General Manager of Public Relation for Volkswagen, there will be no 4motion Passat for the upcoming year. If you want the “feel” of a Volkswagen with agility of all-wheel-drive, perhaps consider the Audi A4.