Tires: the highest-value check
Tires connect the vehicle to the road, and they are the component most likely to be neglected. Check pressure monthly when the tires are cold, meaning before driving or at least three hours after. The correct pressure appears on a placard in the driver's door jamb, not on the tire sidewall — the sidewall number is a maximum, not a recommendation.
Underinflation is the more dangerous error. It increases sidewall flex, which builds heat, and heat is what causes tires to fail structurally at speed. It also lengthens braking distances and accelerates wear at the shoulders. Pressure drops roughly one psi for every 10°F fall in ambient temperature, which is why tire pressure warning lights appear on the first cold morning of autumn.
For tread depth, the penny test still works: insert a penny with Lincoln's head downward into a tread groove. If the top of his head is fully visible, the tread is at or below 2/32 of an inch and the tire is legally worn out. Wet-weather grip deteriorates well before that point, so replacement around 4/32 is a more practical threshold in a climate with regular rain and snow.
Wear patterns diagnose other faults. Wear concentrated in the centre indicates overinflation; wear at both shoulders indicates underinflation. Wear on one edge only usually means an alignment problem, and cupped or scalloped wear often points to worn shocks or struts. Check the sidewalls for bulges or cuts, and do not forget the spare, which loses pressure while sitting unused.
Brakes: listen, feel, and look
Brake pads on most vehicles include a metal wear indicator that contacts the rotor when the friction material runs low, producing a high-pitched squeal under light braking. That sound is a designed warning and means pads are near the end of their service life.
A grinding or metallic scraping sound is different and more serious. It usually means the friction material is gone and metal is contacting the rotor, which damages the rotor rapidly and turns a pad replacement into a pad and rotor replacement. Braking performance is compromised while this is happening.
Pedal feel carries information. A pedal that sinks slowly under steady pressure suggests a hydraulic leak or a failing master cylinder. A soft or spongy pedal often indicates air in the lines or deteriorated flexible hoses. A pedal that pulsates rhythmically usually points to rotor thickness variation, felt through the pedal and sometimes the steering wheel.
Pulling to one side during braking indicates uneven braking force, commonly from a seized caliper slide pin or a collapsed hose. Where wheel design allows, pad thickness can be seen through the spokes; material thinner than about a quarter of an inch warrants inspection. Check the brake fluid reservoir too — a level that has fallen noticeably means either worn pads or a leak, and fluid that has darkened significantly has absorbed moisture and should be replaced.
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Lights, glass, and visibility
Lighting is quick to check and easy to overlook because the driver rarely sees most of it. Walk around the vehicle with the lights on and check low beams, high beams, front and rear turn signals, hazard lights, and side markers. Reversing lights and brake lights need a second person or a reflective surface such as a garage door or shop window.
A turn signal that flashes noticeably faster than normal is the standard indication that a bulb on that side has failed. Brake lights deserve particular attention because a failure is invisible from the driver's seat and directly increases the risk of being struck from behind.
Wiper blades harden and split with age and heat, and they typically need replacing once or twice a year. Streaking, chattering, or leaving unwiped bands are all signs. Check washer fluid and, in winter, use a fluid rated for freezing temperatures — plain water in a washer reservoir can freeze and split the bottle or pump.
Inspect the windshield for chips and cracks. A small chip can often be repaired inexpensively, while a crack that spreads across the driver's line of sight generally requires full replacement. Temperature swings cause chips to propagate, so acting promptly is worthwhile.
Under the hood and under the car
Check fluids with the engine cold and the vehicle level. Engine oil should sit between the dipstick marks and look amber to light brown. Coolant should reach the cold-fill line in the overflow reservoir; never open a hot radiator cap. Brake fluid, power steering fluid where fitted, and washer fluid all have marked reservoirs. A fluid that keeps needing topping up indicates a leak that needs finding rather than a routine top-up.
Inspect the battery terminals for corrosion and confirm the hold-down clamp is tight. Look at accessory belts for cracking, fraying, or glazing, and check coolant hoses by squeezing them when cold — they should feel firm but pliable, not rock-hard or spongy.
Look at the ground where the vehicle normally parks. Clear water dripping in summer is condensation from the air conditioning and is entirely normal. Coloured fluid is not: dark brown or black suggests engine oil, red or pink suggests transmission or power steering fluid, green or orange suggests coolant, and clear oily fluid near a wheel suggests brake fluid, which should be treated as urgent.
Dashboard warnings and a sensible schedule
Warning lamps are colour-coded by severity. Red generally indicates a condition requiring immediate action — oil pressure, coolant temperature, brake system, charging system. Amber or yellow indicates a fault that needs attention but does not usually require stopping immediately. A check engine light that flashes rather than glowing steadily indicates active misfire and should be treated as urgent, because raw fuel entering the exhaust can destroy the catalytic converter.
A workable routine is a quick monthly check of tires, lights, and fluids, taking around ten minutes, plus a fuller inspection twice a year — ideally before winter and before summer — covering brakes, battery, belts, hoses, and suspension. Add a check before any long trip.
The value of this is not that it makes anyone a mechanic. It is that problems caught early are almost always cheaper, and a great many roadside failures announce themselves for weeks before they finally strand someone.