Worst-Case Scenarios: 8 Biggest Car-Breakdown Headaches

By Jerry Edgerton | CBS MoneyWatch

Imagine: It's after dark and you have to pull off the road in unfamiliar territory because your car just stopped running. You've just become a statistic: In any given year, AAA gets about 30 million calls for help from motorists stuck along a roadway somewhere.

The reasons are as numerous as there are parts in a car. But eight specific car problems account for the bulk of those calls. One, of course, is auto accidents, after which drivers often call in for a tow — but apart from trying to drive safely, no one can really prepare for that contingency. The rest of the list, however, offers some lessons for the rest of us drivers.

Timely maintenance is key for almost all of the following automotive headaches. "The best thing anyone can do for a vehicle is regular maintenance," says David Bennett, manager of automotive programs at the national office of AAA. "Nobody can foresee all problems, but regular maintenance improves your chances of avoiding trouble."

Other than accidents, here are the seven most common reasons for being stranded by the side of the road.

1. Battery Trouble

In general, batteries should last for three to five years. But that time can be much shorter if you drive a lot in high heat or extreme cold. To avoid getting stranded by a dead battery, make sure to have your battery checked during any safety inspection or other visit to a dealer or mechanic's shop, Bennett advises — especially if the battery is at least 3 years old. Some warning sign: dim headlights or interior lights and power windows that react more slowly than usual.

2. Lockouts

Advice on this subject is obvious — but the data show that a lot of motorists do not follow it. Get additional sets of keys and store them outside the car in your home and office. If you are going on a road trip, give a set of keys to another member of your party. And if you have a General Motors car, pay the $199 yearly subscription fee for its OnStar service, which allows OnStar operators to unlock your car remotely. (Another reason to subscribe is safety: The system will automatically notify emergency responders if your car is in a crash.) With free smartphone apps that you can download from the GM web site, you can unlock your car yourself through OnStar without having to call an operator.

3. Engine Trouble

This heading covers a multitude of specific problems, of course. But most often it starts with a problem such as a broken hose leaking coolant, leading to an overheated engine. To inspect belts and hoses, look for cracks and peeling on the belts, or softening on the hoses. Also check the levels of transmission and other fluids — usually with a dipstick similar to that for checking oil.

AAA's Bennett suggests guarding against engine trouble by keeping track of your gas mileage from month to month. If you notice a sudden drop in that mileage, it is likely a signal that something is amiss in the engine — or possibly the transmission.

4. Transmission Problems

Speaking of transmissions: Spotting such problems in a modern, computerized car has become trickier. What was readily identifiable as a slipping transmission in earlier vehicle generations can now actually be a problems with sensors or engine control software instead. Nonetheless, if you do feel slipping or a jerk when you put the automatic transmission into gear, get the transmission checked out. And be sure that, during any kind of routine maintenance, your dealer or mechanic checks all fluids, including transmission fluid.

5. Brake Trouble

Nothing is more crucial to your safety than your brakes. Be sure to get your brake pads and rotors checked at least twice a year. The brake fluid needs to be changed every two to three years, depending on recommendations in your owner's manual. Trouble signs: pulling to one side when you hit the brakes, squeaking or grinding noises and a brake pedal that feels too soft.

6. Flat Tires

Worn-down tires make it hard to stop, so be sure to inspect yours regularly. Try the coin test on your tires: Insert a quarter into several grooves across each tire. If part of Washington's head is always covered, you still have 1/8 inch of tread left and can probably drive safely. If you have less tread, think about replacing the tires. A definite danger signal is if you slip a penny into a tread groove and it does not reach Lincoln's head.

If your tires are OK, make sure you keep them inflated to the pressure listed on the placard visible when the driver's door is open. You can boost your gas mileage by 3% or more and make the car safer as well by timely tire checks. To get an accurate reading, check the pressure of tires when they are cold, not when you have been driving. Additionally, check to make sure you have a spare tire and jack. (See Flat Tires: Best Ways to Fix a Flat)

7. Running Out of Gas

What can I say here except: Don't be stupid. If you take your chances on reaching that next gas station, you will probably end up regretting it.

Bonus Tip: Have a Backup Plan

Finally, just in case your precautions don't protect you, make sure you have some sort of roadside service plan. If you are a AAA member, roadside assistance is free for up to four calls per year. You may also have other sources of roadside assistance. Many new cars now come with that service for some period of time, often paired with free maintenance.