Monthly checklist for basic car care

Most of the checks that prevent roadside trouble take only a few minutes each month. Tire pressure, fluid levels, lights, wipers and a quick look for leaks cover most of what is worth checking between services. Do these checks when the car is cold, parked on level ground, and in good light. Your owner manual sets the specific fluid types, tire pressures and procedures for your car, and the manual's figures and procedures take priority.

Tires and fluids

Start with tire pressure, because it affects handling, braking distance and tire wear. Check it when the tires are cold, meaning the car has been parked for a few hours or has been driven only a short distance. Use a gauge rather than judging by eye. The recommended pressure is on the placard, usually on the driver's door frame, and in the owner manual. The number molded on the tire sidewall is the maximum pressure the tire can handle, not the target for your car. Check the spare too, since some temporary spares need a different pressure from the regular tires.

Look at the tread as well. Tread at about 2/32 of an inch is at the legal minimum in many places, and grip on wet roads declines well before that point. Look for uneven wear, bulges, cuts and embedded objects.

Pressure also changes with the weather. As outdoor temperatures fall, tire pressure drops, so a check during a cold snap often reads lower than one taken in mild weather. A tire that keeps losing pressure between checks should be inspected for a leak. A nail in the tread, a damaged valve stem or a bead that does not seal properly are common causes, and a shop can usually find the source.

Check the fluids next. Engine oil is checked with the dipstick as the manual describes, which usually means after the engine has been off for a few minutes on level ground, though some vehicles use a different procedure. Coolant is checked in its reservoir with the engine cold, between the marks. Brake fluid is checked in its reservoir, usually a translucent container near the back of the engine bay. A level that drops between checks can mean worn pads or a leak, so have a technician look at it rather than simply topping up. Top up washer fluid as needed. Use the fluid type the manual names for each reservoir. Keep the brake fluid cap closed except when you need it, because the fluid absorbs moisture from the air. If brake fluid spills, wipe it up at once, because it can damage paint.

Lights and wipers

Check each light from inside and outside the car. Turn the headlights on and switch between low and high beam. Test the turn signals at the front and rear, the brake lights, including the center high-mounted brake light, the reverse lights, the hazard lights and the license plate light. Brake and reverse lights are easiest to check with a helper, or by looking at their reflection in a garage door or a window at night.

A burned-out bulb is usually simple to replace, but a light that flickers, dims or fails repeatedly may point to a wiring or fuse problem. Wipers wear with sun, heat and grit. Streaking, skipping or chattering across the glass means the blades need replacing, and a cracked or hardened blade should be replaced at once. Run the washers with the wipers on and check that the spray hits the windshield rather than the hood. Adjust the nozzles if the spray misses the glass. Good lighting and clear glass matter most at night and in bad weather, when a dim headlight or a streaked windshield cuts down what you can see. Checking them in the driveway at dusk is a practical way to catch problems before they matter on the road.

Leaks and warning signs

Look under the car in the parking space you usually use, especially after it has been parked overnight. Fresh drips tell you more than old stains, and a spot that appears in the same place each time points to a leak worth investigating. Note the color, the location and whether the fluid is oily, watery or sweet-smelling. Colors vary by product, so do not rely on color alone. Engine oil is usually dark and oily, coolant often has a sweet smell and may be green, orange, pink or blue, and brake fluid is thin and usually clear to amber. Power steering and transmission fluid are often red or amber, and dark, burnt-smelling fluid signals a problem.

If a fluid level falls steadily between monthly checks, the cause should be found rather than covered with repeated top-ups. Finally, check the dashboard. With the ignition on, using the key or push-button start, and the engine not running, the warning lights come on as a self-check. Some go out after a few seconds, while others, such as oil pressure and charging, go out only once the engine starts. A light that stays on after starting, or one that appears while you drive, should be checked against the owner manual before you go far. Red warning lights signal urgent problems, while amber or yellow lights usually call for a check soon. A short, regular routine makes change easier to notice, because a new drip, a new noise or a new light stands out when you already know what normal looks like.