Vehicle

Consumer-level vehicle maintenance, consumables and warning indicators.

Scope

Consumer-level vehicle maintenance: consumables, pressures, lamps and the meaning of warning indicators. Brake hydraulics, airbags and fuel system work are outside this repository and always will be.

Common failure modes

• Pressure set from the sidewall instead of the vehicle placard
• A consumable replaced with the wrong part number
• A warning indicator cleared without finding the cause
• A battery that fails on the first cold morning
• Wiper blades that were replaced but not seated

Sections

• Tires, wheels and pressure

  Pressure, tread, sidewall markings and date codes. Every pressure value comes from the vehicle placard, never from this site.

  8 published

• Batteries, charging and 12 V electrical

  12 V battery testing and terminal care with a multimeter. Low-voltage direct current only.

  6 published

• Fluids, filters and consumables

  Consumable filters and fluid level checks that need no pressurised system access.

  6 published

• Lamps, wipers and visibility

  Lamps, wiper blades and washer systems.

  4 published

• Dashboard warning indicators and their meaning

  What a dashboard indicator means, what is safe to continue with, and what needs a stop.

  5 published

All procedures in this category

• What the red brake light on my dashboard means and whether I can keep drivingA red lamp with the word BRAKE in it is not one warning. FMVSS 135, the federal standard for light vehicle brake systems
• How to find your car's maintenance schedule and record what maintenance is actually dueEvery vehicle comes with a maintenance schedule, and that schedule is really two schedules: a normal one, and a severe (
• How to check if your spare tire is there, in good shape and has enough airA flat tire is discovered at the worst possible moment, and that is exactly when most drivers learn their spare has a pr
• How to check the tire sealant and inflator kit your car carries instead of a spare tireMost new cars no longer carry a spare wheel. In its place there is a small case in the trunk holding a bottle of tire se
• Check an automatic transmission fluid level, or establish that the transmission is sealed and has no dipstickChecking automatic transmission fluid is not one job: it is two different outcomes depending on the vehicle. Many automa
• How to check your coolant level without opening the radiator capChecking the coolant is a look, not a job with tools. Most vehicles have a plastic reservoir under the hood with a wall
• How to check your engine oil and work out what oil your car takesChecking the oil is two jobs that people run together. The first is a measurement: is there enough oil in the engine rig
• Check headlight aim against a wall and find the adjustersEvery vehicle's headlights must aim within federal tolerances to ensure visibility and prevent glare for oncoming driver
• How do I check that my lug nuts (wheel nuts) are still tight after a tire shop, a mobile fitter, or a roadside wheel change?A tire shop, a mobile fitter, or your own roadside wheel change tightens the wheel nuts with a torque wrench, but nearly
• How to check your tire pressure and put the right amount of air in your tiresTire pressure is the cheapest safety check on a car and the one people most often get wrong, because the big number moul
• How to check tire tread depth and know when you need new tiresEvery tire sold in the United States carries its own wear gauge, moulded into the tread. Federal Motor Vehicle Safety St
• What battery does my car take, and how do I read the group size and CCA rating before I buy a replacementA replacement car battery has to match the vehicle in five separate ways at once, and the sticker on the case spells out
• Choose and change windscreen washer fluid before freezing weatherSummer washer fluid is mostly water, and water freezes. When it freezes inside the reservoir, the pump or the lines, a t
• Work out why a battery is flat every morning when the battery itself tests goodA battery that reads a normal voltage on a multimeter and is still flat the next morning usually has one of two explanat
• Find the date code on a vehicle battery and work out how old it actually isNobody looks up a car battery's age for fun. The question comes up when the battery is slow to start the engine, when a
• How to read the check engine light codes on your car with a cheap code readerEvery car sold in the United States since model year 1996 carries a self-diagnostic system that watches the emission con
• What does the oil pressure warning light mean, and is it the same as the low oil light?A dashboard light shaped like an oil can, or carrying the words oil or engine oil, is not the same thing as a low oil le
• How to read the tire and loading information placard and work out how much load you have left for passengers and cargoYour vehicle's Tire and Loading Information placard carries more than a tire pressure number. Federal regulation 49 CFR
• Read the treadwear, traction and temperature grades moulded on a tire and know what they do and do not compareMost passenger car tires sold in the United States carry three federal grades moulded into the sidewall: a TREADWEAR num
• How to read a tire sidewall and find out how old your tires areEvery tire carries its own date of manufacture, its size and its limits, moulded into the sidewall. The code that gives
• How to find and replace a blown fuse in your carWhen one thing in a car stops working and everything else is fine — the cigarette lighter socket, the radio, one interio
• How to change the cabin air filter in a car when the air conditioning smells or barely blowsA cabin air filter is the one that cleans the air coming into the car, and it is not the engine air filter. When it clog
• How to change a headlight bulbOne headlight out is one of the few car faults you can often fix on your own driveway for the price of a bulb, and one o
• How to change the battery in a car key fobA key fob that only works when you are standing next to the car is usually a flat coin cell rather than a broken remote.
• How to change the engine air filter in your carThe engine air filter is a paper or fabric panel in a plastic box near the top of the engine, and on most cars it is hel
• How to change your windshield wiper bladesWorn wiper blades are one of the cheapest problems on a car to fix and one of the easiest to put off until it is already
• How to reset the service light, oil change light or maintenance required light on a car after an oil changeMost cars, trucks and SUVs carry a maintenance reminder — a wrench symbol, or a message such as Maintenance Required, Se
• How to test a car battery with a multimeterA multimeter across the two terminals of a car battery gives you one number, the open circuit voltage, and that number i
• What the tire pressure light on my dashboard means and what to do about itOne dashboard symbol is asked to say two completely different things, and almost nobody is told which is which. A lamp t