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5 Cold Weather Myths Debunked

2014 Chrysler 300C in the snow

The mythology around automobiles is pervasive and sometimes fun. When it comes to automotive maintenance, though, those myths can be serious business and a detriment to your modern car. Here are five winter and cold-weather myths that persist, despite being mostly bunk.

Most Batteries Die in the Winter

This is false, statistically, but it's more noticeable because no one likes sitting in a frozen car waiting for help. Most of the cause can be attributed to car owners that haven't kept up on maintenance of their battery rather than being because batteries are more likely to cease working in the cold weather.

Batteries usually have two rankings: cranking amps and "cold" cranking amps. The latter is the amperage the battery can produce, at peak, when the ambient temperature is below zero F. The vast mamority of car owners never see temperatures that low on a consistent basis, so cold cranking amps are generally irrelevant to the gasoline-powered car driving public. Diesel vehicles and those who live where extremes are the norm, of course, should be aware of this standard and buy batteries accordingly.

Now for the real reason for failure. It's rarely the battery. Statistically, more batteries "die" during the summer months, especially August, than at any other time of year because, while the cold deteriorates their state of charge (which can be replenished), the extreme heat over long periods can cook out the battery's electrolyte, which destroys the battery's chemical storage capability.

The most common reason for failure to start in the winter is not the battery, but the connections to and from it. No matter the engine type, be it gasoline or diesel, colder weather means that it takes longer to "crank" it over to start it up. Engines are usually also tougher to turn over because the lubricating oil in them has become thicker, creating more friction. Longer cranks require more power and more power means the battery will generate more heat at the connections. Specifically those terminals and at the connection on the starter solenoid. More heat means the metals used to create those connections on the cables will flex. Enough flexing and they become loose. Loose connections mean less charge for the battery during vehicle operation. The cascading effect eventually leads to a battery being lower than normal and then, after a long sit through the cold, having a harder time producing the power required to crank the engine. Further, those loose connections mean the power is not being delivered efficiently. All together, that means the battery runs out of juice and the car doesn't start.

Sandbags in the Trunk Improve Traction

Well, they do if your vehicle is rear-wheel drive. Today's cars are, for the most part, front-wheel drive, so adding weight to the trunk actually diminishes traction rather than adding to it.

When a car is propelled forward by its rear wheels, adding weight to the trunk presses those tires down into the ground a little better, adding traction. When a car is propelled by its front wheels, the opposite is true. That latter reason is also why adding too much weight to the rear of the car in order to improve traction, even on a rear-wheel drive car, can mean losing control as the front wheels are "lifted" and steering is compromised.

So, unless your vehicle is rear-wheel drive, a couple of sandbags in the trunk will not help.

You Should Start Your Car Mid-Day to Keep It Charged in Winter

There is only one reason this practice would be a good one: you have nothing better to do over your lunch hour, running your car and wasting gas. Chances are that if your vehicle started after spending all night in the coldest temperatures of the day, and got you to work, it will start just fine after sitting in a parking lot or garage during the hottest parts of the day too.

If you find that your car does have trouble starting after just a few hours of sitting, your problems are more likely to be the intense need for a tune up than the weather itself. Check your maintenance intervals and see if it's time for new spark plugs, filters, and the like.

Washer Fluid is Freezing

Most of the windshield washer fluid purchased on the market today has some sort of anti-freezing agent in it. In extreme cold, however, this agent can be overpowered by the temperature and cause streaking on the windshield as it freezes in place. To combat this, on the road, run your defrost on its highest temperature and fan settings. Then, if the weather will persist, stop at the paint store and buy some methyl alcohol and add a little to the washer fluid's reservoir. Most windshield washer fluid is about 40% methyl alcohol, so adding a few more ounces to a quart-sized reservoir can up this to 60% quite easily. The more there is, the less likely it will freeze. Treating the windshield with water-repellent film (ala "Rain-X") might also help.

My Squirt Nozzles Stopped Working; They Froze

If your windshield washer squirt nozzles are working and then seem to stop suddenly, it's not likely that they've frozen. It's more likely that debris have accumulated in the lines or the nozzles and are blocking the fluid. Most likely that junk is from reflux after the check valve on the fluid line fails.

Your windshield washer fluid lines have a check valve that prevents the fluid from running backwards, back to the reservoir. This has two purposes: first, it keeps the lines from "sucking in" stuff like slush and dirty water; second, it keeps the lines filled with the washer fluid and its anti-freeze additive (see above), which prevents the lines from freezing.

If the check valve fails, then when you stop using the windshield washers, anything lying against or near the nozzles can be "sucked in" and begin building up in the reservoir tank or the lines. This also means that when not in use, the lines can become frozen since there is no anti-freeze in them.

The fix is simple. Replace the check valve (usually an easy five minute job) and leave the vehicle in sunlight or a warm area to de-freeze. Alternatively, run the engine and allow the hood to "heat" and defrost the lines for you, then run the washers and let them re-fill with anti-freeze washer fluid.

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