How to winterize a car

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The winter months are hard on your vehicle. Cold temperatures, dirt, and road-salt residue can all cause problems. However, there are some simple checks and maintenance items you can do that will help your vehicle stay in top condition.

Good Visibility is Vital

If your wipers are leaving streaks of water on the windshield, or if the wiper-blade rubber shows any signs of cracking or stiffness, replace them with a new set. Use a brush and a scraper to remove ice and snow from the windshield rather than your wipers; a heavy load of snow (or ice sticking the blades to the glass) can overload the motor. If the vehicle is parked outside, lift the wipers off the glass before an overnight snow to keep them from freezing to the windshield.

With dirt, mud, and salt residue being kicked up off the road, it's likely that you'll be using your windshield washers a lot. Be sure to keep your windshield washer reservoir filled with a washer solution that contains an antifreeze agent. (The standard blue stuff will suffice; just don't use water, as it can freeze in the washer lines.) Make sure that your car's heater is functioning properly and that plenty of warm air is being directed to the windshield when it's in the defrost mode. If your car has a separate A/C button, turn it on when defrosting; even with the temperature set to hot, the air conditioner dehumidifies the air which speeds defogging. (Most cars will automatically turn on the air conditioner with the defroster.) Don't use the recirculate mode.

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Finally, check that all the vehicle's lights are working properly and clear of snow and ice, so that you'll have optimum visibility at night and other motorists will be able to see you.

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Consider a Switch to Winter Tires

If you drive a lot in slippery conditions, it's a good idea to replace summer or all-season tires with a set of dedicated winter tires, which have tread patterns and rubber compounds specially designed for optimum traction on slick roads. Winter tires typically have shorter tread life and generate more road noise than the all-season tires that your vehicle came with, but the extra safety they provide is generally worth the compromise. (See our tire ratings.)

If you'll be using winter tires, you might consider having them mounted on inexpensive steel wheels. This will make it easier to switch between the two sets of tires, plus it will save your more expensive alloy wheels from the damage inflicted by harsh winter conditions.

For extreme conditions, studded snow tires or even tire chains may be warranted. Because they can be tough on road surfaces, check if they're legal in your area before making the investment. Some states require snow chains on certain roads.

Keep the Battery in Good Shape

Cold temperatures reduce your battery's cranking power—in fact, at about zero degrees F, your battery only has about half the cranking power it has at 80 degrees. At the same time, the thickened oil in a cold engine makes it harder to turn over. Following are a few easy checks to make sure it's in as good condition as possible.

On conventional batteries, remove the plastic caps on top of the battery and check the fluid level (see your owner's manual). If the fluid is low, add distilled water. On maintenance-free batteries, check that the window at the top of the battery indicates a fully charged state (check in your owner's manual). If it isn't, have the battery professionally tested at a service station, auto parts store, or repair shop. It may just need to be charged. But if it's defective, it's best to replace it before it goes completely dead. (See our battery Ratings and buying advice.)

If you'll be using winter tires, you might consider having them mounted on inexpensive steel wheels. This will make it easier to switch between the two sets of tires, plus it will save your more expensive alloy wheels from the damage inflicted by harsh winter conditions.

Make Sure You Use the Right Engine Oil

Engine oil thickens when cold, making it harder for the engine to turn over. Modern cars use multi-weight oil that is suitable for a wide range of temperatures, but some manufacturers recommend specific grades of oil for specific temperature ranges. Check your owner's manual and plan your oil changes so your engine has the right grade of oil for the right time of year.

If you expect to experience extremely low temperatures, you can have an engine block heater installed in the engine. When plugged into a household electrical outlet, it keeps the engine oil from getting cold and thick.

Check Your Cooling System

Extreme cold can cause rubber parts to become brittle and fail. When the engine is cold, check the radiator and heater hoses for cracking, leaking, or contamination from oil or grease. The hoses should be firm yet pliable when you squeeze them. Replace them if they feel brittle or overly soft.

For most vehicles, the cooling system should be flushed at least every two years (check your owner's manual). This helps keep corrosion from building up in the system. If a flush is almost due, have it done before the cold weather hits. The system should be refilled with a mixture of antifreeze and water, typically in a 50/50 ratio. (Coolant can be purchased either full-strength or pre-mixed; be sure you know what you are buying.) This will keep your coolant from freezing to well below zero. Colder conditions, however, can call for ratios of 60/40 or 70/30. Check your owner's manual or the back of the antifreeze container. Under no circumstances should you use a higher antifreeze-to-water ratio than specified by the manufacturer.

Prevent Freeze-ups

Water can get into door and trunk locks and then freeze, locking you out of the vehicle. To prevent this, lubricate the locks with a silicone spray or door-lock lubricant. If they're already frozen, use a lock antifreeze product to thaw them.

Protection for Inside and Out

The dirt and salt of winter can attack your car's paint finish. To help protect it, give the car a fresh coat of wax before the snow flies and wash it regularly during the winter months. With modern vehicles, rust isn't as big a problem as it used to be, but it's still a good idea to have the wheel wells and underbody washed regularly to prevent road salt from building up. If your vehicle has alloy wheels, apply a coat of wax to them to help prevent pitting and corrosion.

If you don't already have floormats in your car, you should pick up a pair. Even inexpensive ones will protect your car's carpet from the water and mud that tends to get tracked into the vehicle. For maximum protection, a set of rubber all-weather floor mats will keep salty snow from seeping through the carpet and into the car's floorboards. If you do buy aftermarket floor mats, be sure they won't interfere with operation of the pedals.

Let the Engine Warm Up

In years past, cars would cough, stumble, and stall if not given sufficient time to warm up. Modern cars can be put in gear and driven away as soon as they are started, but that doesn't mean you should skip the warm-up entirely. A brief bit of idling time before you drive gives the oil a chance to heat up, thin out and flow more smoothly, and you'll want that to happen before you ask your engine to do any serious work. Letting your car idle while you brush the snow off of it should be sufficient. (By the way, there's no need to rev the engine; it'll warm up just fine at idle.) If your car idles higher than normal when first started, waiting until the idle speed drops before putting the car in gear will save wear and tear on your automatic transmission.

Drive gently until the temperature gauge starts to move off the bottom peg or until the cold engine light (usually blue) goes out. Remember, cars can still overheat in winter, especially if the radiator grille is clogged with snow.

Visit our guide to winter driving.