Mechanical failure is an inconvenience anytime it occurs, but it can be deadly in the winter. Preventive maintenance is a must.
The following preventative maintenance is recommended:
Get engine drivability problems such as hard starts, rough idling, stalling, and diminished power corrected . Cold weather makes existing problems worse. Also, ensure engine efficiency by replacing any dirty air or fuel filters.
Put a bottle of fuel deicer in your tank once a month to help keep moisture from freezing in the fuel line. A full gas tank also helps to keep moisture from forming.
Change your oil and oil filter as specified in your owner's manual, and more often (every 3,000 miles) if your driving is mostly stop-and-go or consists of frequent short trips.
The cooling system should be completely flushed and refilled about every 24 months. The level, condition, and concentration of the coolant should be checked periodically. (A 50/50 mix of anti-freeze and water is usually recommended.) DIYers, never remove the radiator cap until the engine has thoroughly cooled. The tightness and condition of drive belts, clamps, and hoses should be checked by a professional mechanic.
Replace old blades. If your climate is harsh, purchase rubber-clad (winter) blades to fight ice build-up. Stock up on windshield washer solvent-you'll be surprised how much you use. Carry an ice-scraper.
The heater and defroster must be in good working condition for passenger comfort and driver visibility. Newer models have a cabin air filter that should be replaced periodically. Check your owner's manual for the location and replacement interval.
The only accurate way to detect a weak battery is with professional equipment. Routine care: Scrape away corrosion from posts and cable connections; clean all surfaces; re-tighten all connections. If battery caps are removable, check fluid level monthly. Avoid contact with corrosive deposits and battery acid, and always wear eye protection and rubber gloves.
Periodically inspect all lights and replace burned out bulbs Be sure to clean road grime from all lenses, using a dry rag to prevent scratching.
Your vehicle should be placed on a lift and the exhaust system examined for leaks. The trunk and floor boards should be inspected for small holes.
Examine tires for remaining tread life, uneven wearing, and cupping; check the sidewalls for cuts and nicks. Tire pressures should be checked once a month when they are cold, before driving for any distance. Regularly rotating your tires is also recommended.
Finally, carry emergency gear gloves, boots, blankets, flares, a small shovel, sand or kitty litter, tire chains, and a flash light. Put some bottled water and a few "high-energy" snacks in your glove box.