Most of the energy released by burning gasoline in an internal combustion engine is wasted, which is why everything under the hood gets hot whenever you drive.

It’s the job of engine coolant to keep it from getting too hot. But old coolant, or coolant that’s been worked hard in extremes of temperature, breaks down, gets dirty, and loses its ability to transfer heat from the engine to the radiator. That’s why you need to replace it occasionally to avoid losing your cool––and your engine’s.

Start with a cold engine, or one that’s cool. Never open the radiator cap when the engine is hot. Now open the cap slowly. You might hear a hiss as the pressure in the cooling system escapes.

Next find the drain plug or petcock on the bottom of the radiator. If there isn’t one, disconnect the lowest end of the bottommost radiator hose. Drain the coolant into a container. Check your local laws regarding the disposal of coolant. Antifreeze is toxic, and should not be splashed around where kids or animals can get in it. Auto repair shops will often take your used coolant for recycling. More...

Like any test, the smog test is a scary proposition. Required every two years in some California counties and on vehicle resale statewide, smog checks have gone a long way in reducing emissions in this vehicle-obsessed state. But, that doesn’t reduce the angst when you drive into your local smog check station.

Passing a smog test is as easy as passing any test, as long as you come prepared. Here are some guidelines that should help you ace this test.

Make sure your vehicle is running well. If it’s missing, choking, belching smoke, get it to a repair shop before you go anywhere near that smog inspection bay. An appointment for a tune-up prior to your smog check can save you a lot of time and trouble, not to mention money.

Take the long route to your smog test. Vehicles run at peak efficiency when they’re warmed up, a condition that can be reached in less than 10 to 15 miles of driving. If possible, hit the freeway/highway on your way to the station, to help clear out the pipes. More...

It’s hard to keep your cool on a hot day when your car’s air conditioning isn’t doing its job. If yours can’t put out air that’s at least 40-50 degrees cooler than the outside temperature, or if it can’t maintain that temperature, then you might have a problem.

You could have a real problem if you decide to try to fix your A/C yourself. The entire system is under high pressure, and the job can literally blow up in your face. Depending on who you trust to do the work, and what your A/C needs to get back up to speed, it can cost a little or a lot. That’s why it’s a good idea to take preventive steps ahead of time.

Get your A/C serviced on a regular basis, even if it’s working fine. Your car’s service schedule will specify how often the coolant and belts should be changed. Most cars should have the refrigerant recharged no more than four years after the date of manufacture, and every two or three years after that.

Make sure the A/C radiator is clean. That’s the small radiator that sits in front of the big one that cools your engine. Because it’s the first thing that incoming air hits, it’s the first thing to get clogged up by dirt, leaves, and bugs. Every time you wash your car, hit the A/C radiator with a strong stream of water, and use a wooden toothpick to remove stubborn bits.

It sounds weird, but make sure you run the A/C now and then in the winter. This keeps the O-rings and seals in the system lubricated so they’ll be in good working order come the summer. Also, it’s better to find out your A/C system needs work when you don’t need it and have time to get it fixed.

Keep an eye on the A/C belt, and tension it if it’s loose. Inspect it as you would any other belt, looking for cracks, splits, or frayed sections.

Finally, don’t worry if there’s a puddle of water under the passenger side of the car after you use the A/C; it’s almost certainly condensation draining out of the A/C condenser, and it’s normal.

Doing your own tune-ups is a great way to save money and get a feeling of accomplishment. But you shouldn’t just jump into a tune-up without doing your homework first. Here are some tips to make your next tune-up go more smoothly.

Get a shop manual

Want to really screw up your car? Start messing with it without having a clue what you’re doing. A lot of things on a car affect other things, and if you get something wrong, it can have a domino effect that can bring your car to its metaphorical knees. A shop manual will tell you what to do, and in what order, to avoid making things worse than they were when you decided you needed a tune-up.

Read the shop manual

This might seem like a no-brainer, but some guys need to be reminded to read the step-by-step instructions for the particular job they’re doing before they start, to make sure they fully understand what needs to be done, how it’s done, and what tools and parts are needed to do it right.

Have the parts on hand

Don’t even think about starting a specific tune-up task unless you have the parts you’ll need to complete it. You might think your local auto-parts store will have what you need, but you might be wrong—and there you’d be, with your car missing a few key parts, and you calling all your buddies to get a ride to the store that does have it. More...

For a lot of people these days, buying a new car to replace that old one in the driveway isn’t an option. Also, it’s often cheaper in terms of monthly outlay to keep that old faithful ride running than to take on several years of payments and a higher insurance premium. Here are some pointers to a long and happy relationship with your older car.

Find out all you can about your particular year and model. Talk to your buddies, consult a professional mechanic, and surf the net for forums dedicated to your car––but remember, people with gripes post more than people who are satisfied with their cars, so don’t panic if a handful of posts are negative.

Go to the library and look at back issues of Consumer Reports, which publishes an annual car buyers guide with data on reported problems going back a number of years. Knowing what goes wrong with other people’s cars can help you avoid trouble with yours. Your library might also have shop manuals you can check out.

Now’s not the time to skip scheduled maintenance. Regular changes of oil, coolant, and other fluids are vital to the health of any car, new or old. Keep an eye on belts and hoses to prevent small problems from turning into big, expensive ones. Pay particular attention to the recommended interval for changing the timing belt, which if it breaks usually takes some valves out with it. [more[

Small things like chipped glass, broken trim, and rips in the seats or carpets don’t seem like very big deals when they happen, but if you let them accumulate they can overwhelm you, and before you know it you’ve lost the will to fix them all. Keep on top of repairs, and use each one as an opportunity to check out nearby parts of the car for potential problems. Don’t ignore those funny noises you hear sometimes. Check them out before they get louder––and costlier.

Keep your car clean. Wash and wax it regularly to preserve the paint and prevent rust. Keep an eye on the chrome, too. Spots of dirt that stick to it can corrode the thin layer of chrome and expose the metal underneath to the elements. Keep the interior clean, especially the carpets, which can be worn down by dirt ground into them by your feet.

Finally, even though your old car might not be the quickest or flashiest thing on the road any more, treat it the way you’d treat a favorite old pet, with respect and affection. You can stand on the loud pedal now and then, but don’t forget it’s an older car. Instead, think about the monthly payments you don’t have to make, and the lower insurance rates you’re paying—and when the economy picks up and you can finally afford a new car, you’ll get that much more for your old one.