DIY Car Checks You Can Do Without Any Special Tools

Worn tyres are one of the most common causes of poor wet-weather handling and increased stopping distances. The legal minimum tread depth in the US varies by state, but most safety guidance recommends replacing tyres before they reach 2/32 of an inch — and ideally at 4/32 for better wet traction.

A quick way to gauge this without a gauge: insert a penny into the tread groove with Lincoln's head pointing down. If you can see the top of his head, the tread is too low. A quarter gives you a slightly more conservative warning — if you can see Washington's full head, you're getting close to the replacement zone.

Also take a moment to look for uneven wear across the tyre surface. Wear concentrated on one edge often signals an alignment or inflation issue worth mentioning at your next service appointment.

A tyre can lose significant pressure and still look fine to the naked eye. The recommended pressure for your tyres is printed on a sticker inside the driver's door jamb — not on the tyre sidewall, which shows the maximum pressure, not the target.

While you genuinely need a tyre pressure gauge (available for a few dollars at any auto parts store or gas station) to get an accurate reading, you can still do a basic visual check: look for any tyre that sits noticeably lower than the others, or feels soft when you press firmly on the sidewall. These are signs to investigate immediately. If your car has a TPMS warning light illuminated on the dash, don't ignore it — check all four tyres.

Correct pressure improves fuel economy, tyre life, and handling. It's worth the two minutes it takes.

Most engines have a dipstick — a long, looped handle near the front of the engine bay, often yellow or orange. Park on level ground, wait a few minutes after shutting off the engine, then pull the dipstick out, wipe it clean with a rag or paper towel, reinsert it fully, and pull it out again. The oil should sit between the two marks near the bottom of the stick.

While you're at it, look at the oil on the stick. Fresh oil is amber-brown and translucent. Very dark, gritty-looking oil or oil with a milky, frothy appearance can signal problems — the latter sometimes indicates coolant mixing with oil, which warrants prompt professional attention.

Check your owner's manual for your car's recommended oil type before topping up. Using the wrong viscosity can cause engine wear. For a broader look at fluids that often get overlooked, see this guide to coolant, transmission fluid, and other critical fluids.

The washer fluid reservoir is a translucent plastic tank in the engine bay — most are clearly marked with a windshield symbol. Topping it off is straightforward. Use a washer fluid formulated for your climate; plain water can freeze in winter and doesn't clean as effectively.

While you're at it, run your wipers and watch how they perform. Streaking, skipping, or squeaking are all signs the rubber blade is degrading. You can also manually lift each wiper arm and run a finger along the rubber edge — cracks, tears, or a stiff, hardened feel mean it's time for a replacement. Wiper blades are one of the most affordable and easiest parts to swap yourself.

Clear visibility in rain is a direct safety issue, and worn wipers can make wet-weather driving significantly more dangerous.

A burned-out brake light or turn signal is easy to miss from the driver's seat but can create real safety risks — and in most states, it's also a ticketable offense. Do a quick walk-around check about once a month.

Turn on your headlights and walk around the car to confirm both low-beam and high-beam lights work. Then switch on your hazard lights and check all four turn signals and brake lights are flashing correctly. For brake lights, park near a garage door, wall, or reflective surface and press the brake pedal — you should see red light reflecting back.

Replacing a bulb is often something you can do yourself, but some newer vehicles make bulb access awkward enough that a shop visit makes more sense. If you notice a dashboard warning light related to your bulbs or brakes, learn what it means before dismissing it.

Most modern brake pads include a small metal tab called a wear indicator. When the pad wears thin enough, this tab contacts the rotor and produces a high-pitched squealing or squeaking sound during normal braking. If you hear it consistently, it's a signal the pads are approaching the end of their life.

A grinding or growling sound during braking is more serious — it often means the pad material has worn through completely, and metal is contacting metal. This can damage the rotor and compromise stopping ability. Don't delay getting it checked.

You can often see the pad thickness through the spokes of the wheel without removing anything. If the pad looks very thin — less than a quarter inch — schedule an inspection. Brakes are not a DIY repair for most drivers; a qualified mechanic should confirm their condition. For more context, read about how brakes work and the signs they need attention.

After your car has been parked for a few hours, glance at the ground underneath it. A small puddle or spots on the pavement can tell you a lot — if you know what to look for.

Clear water dripping from beneath is usually condensation from the air conditioning system and is generally harmless. An oily, dark brown or black puddle near the center or front of the car could indicate an engine oil or transmission fluid leak. A bright green or orange liquid is likely coolant (antifreeze) — a leak here should be addressed promptly since low coolant can lead to overheating. Reddish fluid is often power steering or transmission fluid.

If you spot anything other than clear water, describe the color, location, and approximate amount to a mechanic. You don't need to diagnose it yourself — just report what you see.