Which car jobs can I do myself, and which should I leave to a garage?

Seven pages in this library bear on this question. One is about where to start if you want to work on your own car, one is about the air filter a shop holds up at the counter, one is about the temperature gauge climbing, one is about the one garage that gets your small jobs, one is about the schedule in the owner’s manual, one is about changing a flat tire, and one is about tire pressure and the spare. They do not all agree, and where they do not, this answer says so.

Begin with an oil and filter change, and if the car has to be lifted, put it on jack stands before any part of you goes underneath. That is the first page’s own line. If you cannot do this work, or do not want to, it is not asking you to, and paying a shop is a fair choice.

Never get under a car that is held up only by a jack. After you lift it, put jack stands of a suitable weight rating under it, put a chock behind each wheel that stays on the ground, and work on flat, hard ground, not grass. Put the car in park with the handbrake on, use the lifting points in your manual, and give the car a firm push before you go under it to check it is stable. An Australian government product-safety guide says that getting under a car on a jack alone can be fatal, and an Australian motoring association gives the same rule. If a car comes down on someone, call 911 in the US or 999 in the UK straight away. The page adds that this costs a few minutes and some money, and that when the safe answer costs this little, you take it.

Why the oil and the filters come first. Some people say oil and filters are the least risky place to start, and that the simplest jobs are the ones where doing it yourself saves the most, because some people say shops charge a high hourly rate and a minimum labour time even when the part is trivial. Some people also say the tools for the basic jobs are inexpensive and reusable, and one person says not to skimp on sockets. One person says auto parts shops lend tools, and another says the deposit can go on a card and comes back when you return the tool. One person says a repair manual for their exact car paid for itself on the first job. People disagree about whether the oil change itself is worth the effort: one side values doing your own oil as a skill: it saves money, and you know the job was done properly, and the other says it often costs more in time and hassle than a shop charges, especially once the cleaning up and the disposal of the old oil are counted. What decides it, they said, is how you value your time against the money, whether you have a proper way to get rid of the used oil, and how much you want to control the job yourself.

The page’s first step costs nothing: do not buy a tool yet. Check where you could work, a driveway or garage, and whether your lease or building lets you. Then watch one video for your exact car, start to finish, with no wrench in your hand, and write down every tool it names. If the job needs the car lifted, jack stands go to the top of that list.

The old oil. Do not pour it down a drain or onto the ground. The US Environmental Protection Agency says used oil from one oil change can contaminate a million gallons of fresh water, advises checking with local auto maintenance shops, waste collectors or local government waste officials to find where you can drop it off for recycling, and says to keep it in a leak-proof container. One person says getting rid of used oil is not as easy as it used to be, so find your drop-off point before you drain anything.

The air filter is the other first job, and it is not equally easy on every car. Many people say replacing an engine or cabin air filter is a simple job that takes minutes and costs a fraction of what a dealership or quick-lube shop charges, and many say a video is an effective way to learn it for your car. Some people say that on some models the filter sits where it is hard to reach and the job takes longer; some say the cabin filter on some cars means taking the whole glove box out. The engine filter and the cabin filter are two different parts, and your manual’s schedule lists both. The US Department of Energy says that replacing a clogged air filter on vehicles with fuel-injected, computer-controlled gasoline engines, which covers cars made since the early 1980s, or on diesel engines, does not improve fuel economy, but it can improve acceleration.

If you would rather pay for it, ask to be shown the part where it sits in your car. Many people describe a shop holding up a dirty air filter as the reason for a sale, and say the filter may not have come from their car, or may not have needed changing at all. That is what people describe; it says nothing about your shop, and some people say a high price is not proof of fraud. One person says a dealer’s recommendation can come from the service history rather than from looking at the filter. The page’s counter checks: ask to see the old part; ask to see it in the car, because one person says that if you stay with the car, or watch the mechanic take the part out, it is hard to swap in a filter made dirty beforehand; follow your own car’s service schedule, not a general rule such as a fixed mileage; read the itemised list and say no to what you do not want.

Brakes and steering: the one place people split. Some people say replacing the front brakes makes one of the simplest and best-value first projects, if you watch the tutorials thoroughly, with a basic socket set and a clamp to push the piston back. Other people say brake and steering work should be left alone by beginners, or by anyone not comfortable with mechanics, because when it goes wrong the failure can be catastrophic. One person says not to attempt brake or steering work at all unless you are already highly experienced. The first page does not start you on brakes and gives no brake procedure; your car’s manual does that. One person says the brake pedal has to pump firm again before the car moves. What decides it, people said, is how much you already know, how rusty the car is, and whether an experienced person can stand beside you. One person warns that some newer cars use one-time-use bolts on the caliper that can shear if reused, and one that cars with an electronic parking brake need their service mode switched on first, or the part can be damaged.

The hard part is not the bolts. Some people say the physical work is the easy part of a repair, and that working out what is wrong is harder. Some people say doing it yourself can cost more, either because you lack a specific tool or because you misdiagnose the problem and end up paying a tow. Some people say simple jobs often turn into bigger ones, a bolt rusted solid or a fitting that strips, and some say a little knowledge is dangerous: a skipped or misunderstood step can turn a small, cheap problem into an expensive one, or into a safety hazard. One person says a timing belt fitted wrongly can bend engine valves and cost more than a professional’s labour would have. Some people say to have a knowledgeable friend nearby for the hairy moments. That is one more reason the first jobs on these pages are the scheduled ones, the oil and the filters, where nobody has to guess what is wrong.

Will doing it yourself void the warranty? In the United States, the Federal Trade Commission says a company cannot void your warranty or deny coverage solely because you had repairs or service done by someone not associated with the company, and its page names a do-it-yourself fix as one of the choices you may prefer, beside an independent repair shop. The FTC adds one limit: a company can still refuse to cover a defect or damage that was caused by the third-party parts or services. One person says lack of paperwork for the maintenance can complicate a warranty claim even when the work itself does not void it. Read your own warranty booklet for its wording. Outside the United States the rules differ and these pages do not cover them.

If you have a flat, change it only once you are completely off the road, loosen the wheel nuts a turn while the tire is still on the ground, then lift the car, and keep every part of you out from under it. Loosen the lug nuts before you lift the car asks you to read its safety part first. Do not change a flat in or near a lane of traffic. A US state transport department says it is better to ruin a tire or a wheel than to risk being hit by another vehicle, and says that if you cannot get out of the lane, you should stay in the car and call for help. On a UK motorway, the Highway Code says not to try repairs and to leave the vehicle by the side furthest from traffic if that is safe. Follow the one for where you are. Once you are completely off the road on level, firm ground, a vehicle maker’s owner’s manual says to switch on the hazard lights, put the car in park with the handbrake on and the engine off, block the wheel diagonally opposite the flat at the front and back, and not let anyone stay in the car while it is on the jack; anyone with you should wait well away from the road. Never put your body, or any part of it, under a car held up by a jack. If a car comes down on someone, call 911 in the US or 999 in the UK at once.

The manual says to turn each nut about one turn counterclockwise with the wheel wrench and not to take any nut off until the tire is off the ground. Some people say the reason is that on the ground the wheel cannot spin while you push on the wrench, and the jack is not strained by it. The manual says to put the jack only on the car’s designated jacking positions, never on the bumpers or any other part. Some people say small scissor jacks are unreliable because a slight shift can drop the car; one person warns that a scissor jack on a slope or on gravel will fall, and another suggests a piece of plywood under the jack on soft ground. Then put the spare on, tighten the nuts by hand, lower the car, and tighten the nuts in a crisscross pattern, every other nut, going round once more to check each one. For a tire change you do not need to be under the car at all, and one person says every step can be done from the side. Many people suggest sliding the wheel you have just taken off under the car, near the jack, as a backstop, and one person points out it must be the whole wheel with its rim, not the rubber tire alone; some call it a sound emergency backup if the jack fails and you have no stands, and others call it dangerous and say only rated stands should hold a car if anyone is going under it. Either way it is a backstop for someone kneeling beside the car, not a reason to go under it. On torque, the manual gives a figure for its car and says to have it checked by a workshop, and people disagree about whether you need a torque wrench for a temporary swap. A compact spare is for temporary use: the manual says it must not be driven over 50 mph (80 km/h) and that the original tire should be repaired or replaced as soon as possible. That page is for an ordinary passenger car that has a spare, a jack and a wheel wrench, and for someone who is already completely off the road. If you cannot physically kneel, turn a wrench or work a jack, or you are alone somewhere you do not feel safe, roadside help is the better choice. It does not cover a car with no spare, nuts that will not turn, or freeing a person from under a car; working under a car is a different job, and the stands are covered above.

Fill your tires to the number on the sticker in the driver’s door jamb or in the owner’s manual, not the number on the tire, and check the spare’s air at the same time. Check the spare, and fill to the door sticker asks you to read its safety part first. Tires can fail while you fill them. Some people say that if you hear a sound like a zipper while you inflate a tire, you should stop at once and move away from it. One person warns that a tire driven flat for long enough to damage its inside can burst when it is pumped up, and says it belongs in a safety cage for inflating. If you have driven on one flat, do not pump it up yourself; take it to a tire shop. A vehicle maker’s owner’s manual says a tire that is badly under-inflated, by about 10 psi (70 kPa) or more, risks heat build-up, a blowout and its tread coming apart. The US Department of Energy’s fuel economy site says not to use the maximum pressure printed on the tire’s sidewall, and some people clarify that the sidewall number is a limit, not a point where the tire bursts. The sticker is for the tires the car came with; some people warn that it may not apply if you changed the tire size or the load rating. Check the pressure cold: the manual says the car should not have been driven for at least three hours, or should have been driven less than a mile, and that warm tires normally read 4 to 6 psi higher, so do not let air out of warm tires to bring the reading down. Many people say a spare slowly loses air and can be flat by the time you need it, and the manual says to check the spare each time you check the others. The spare may not use the same number: the manual’s compact spare is filled to 60 psi and must not be driven over 50 mph (80 km/h), and the label on your spare and your own manual have the number for yours. If your car came with a sealant kit and no spare, only the first half of that page is for you. It does not say what a dashboard warning light means, and if you tow, carry heavy loads, drive heavy trucks or have fitted wheels and tires that are not the size the car came with, the sticker may not be the whole answer.

Read the manual before you decide what is due. The manual outranks the sticker says your maintenance schedule is the owner’s manual, not the sticker on the windshield and not the folklore. Its people say the 3,000-mile oil change is a standard from older engines and older oils, and that modern engines on the synthetic oil most now specify run intervals several times longer; the manual states the real number for yours. They give honest exceptions: severe use shortens the interval (dusty roads, heavy idling, towing, and short trips), and time matters when mileage does not, so a low-mileage car still wants fresh oil roughly annually. They say to use exactly the oil spec and viscosity your manual names. Two things they say are worth finding in the manual before they cost you: whether your engine has a timing belt or a chain, because a belt has a replacement mileage and past it a snapped belt can destroy the engine in one instant; and the transmission-fluid service, because they say “lifetime” and “sealed” fluid labels are marketing, not chemistry. If your car is under warranty, they say to check whether the fluid service must be done through the dealer to keep it valid. People disagree even among those who have read the manual: one camp says the manual’s number is the number, and the other says to change early because oil is cheap and engines are not. A newer car in ordinary use earns the manual’s full interval; an older engine, severe conditions or an unknown service history earn the early-change camp’s caution.

When the temperature gauge climbs, do not open the cap on a hot engine. Pull over before the gauge reaches red is the page for that moment.

Never open the radiator cap, or the coolant reservoir cap, on a hot engine. The cooling system is under pressure. AAA in the US says that if you remove the radiator cap while the coolant is hot, it can spray out and severely burn you; the RAC in the UK says opening it while the engine is hot can cause serious injury from steam and scalding liquid. AAA says to wait about 20 minutes before checking anything under the hood, and the RAC says at least 30 minutes before reopening the engine compartment, and longer in hot weather or after a bad overheat. Both give a minimum, and waiting longer costs nothing. Even when the engine is cold, the RAC says to open the cap slowly with your hand covered. Get everyone out of the car and away from the road. The RAC says on a motorway to leave at the next exit or pull into a service station, and to switch on the hazard lights, and in the UK to leave by the left-hand door, in hi-vis jackets if you have them. If you cannot get off the road safely, or you are in danger, call 911 in the US or 999 in the UK (your local emergency number elsewhere). Otherwise call your breakdown or roadside service.

The order the page gives: pull over where it is safe, turn off the engine and put the hazard lights on; get everyone out and away from the road; do not open the hood, or touch the front of the car, for at least the minimum above; once it is cold, check the coolant level in the reservoir and, the RAC says, top it up with coolant or a mix of water and coolant, and look under the car for leaks if the reservoir is empty; do not drive on. The RAC says never to continue driving an overheated car, and AAA says adding coolant may give temporary relief but a professional has to diagnose the cause. If you cannot pull over right away, AAA says to turn the air conditioning off and the heat on, which makes the car uncomfortable but can help the engine cool slightly; that is a bridge to a place to stop, not an alternative to stopping. Many people say the same about the heater, and say it is temporary and for minor overheating. One person who works as a mechanic calls it one of the worst pieces of advice, because it masks the problem while the engine cooks inside and risks head gasket failure; the person who wrote the tip answered that it has saved them thousands in repairs.

Both AAA and the RAC say to turn the engine off, and one person argues that for mild overheating idling with a reduced load and the heater on keeps the water pump moving coolant. The page calls that a reason to know your car, not a reason to override what both organisations say. Some people warn that cold water poured over a hot engine block, or into a hot radiator, can crack the block or cause severe burns from steam, and the RAC says to avoid pure cold water on a hot radiator because it can damage the engine. Waiting for it to cool by itself costs nothing. One person warns against stop-leak powders and the egg-in-the-radiator hack, saying they clog the system. If a car that has always been dependable abruptly shoots into the red, one person says that points to a serious failure such as low coolant or no circulation, so pull over and switch off.

For the jobs you hand over, give one independent garage your small jobs and keep going back. Give one garage the small jobs first says the defence against a padded bill is not knowing more than the mechanic; it is a garage that wants you back. Some people say a long relationship with a single reputable garage lowers the chance of being cheated, because repeat business is worth more to them than one padded bill, and others say the way in is the small jobs, the oil and the yearly check, done at the same place until you are a face and not a stranger. The page also keeps how it fails: one person says it backfires if the first choice was bad, and puts it plainly, loyalty to a bad garage is just paying a bad price for longer. Some people warn to pick the garage by research and word of mouth first, and stay only once it has earned it; one person says an online score is a poor guide.

Four checks need no car knowledge: ask to see the old part; for any big quote, take the car elsewhere before you agree; check the work afterwards, the fluid levels, or one person’s dot of nail varnish on a bolt of the part that is meant to be replaced, because if the dot is untouched, it was not; and look up what the labour should take before you agree. One person says a part shown to you is not proof either, because you cannot tell an engine component from a piece of a vacuum cleaner, which is why the second check matters. Some people call the dealership the dear option; one person says the dealer is sometimes the only place for a computer fault. Some people say chain shops run sales quotas that drive the upsell, and one person says quick-lube shops over-tighten the drain plug with air tools and strip threads. Independents are “hit or miss” in some people’s words, which is why the method is to pick one and stay.

If you think a shop cheated you. The garage page names one route: if the bill came before you agreed to the work, one person says dispute the card payment and find the body that regulates repair shops where you live. What your legal rights are is not covered in these pages. This library lists ReportFraud.ftc.gov in the US, where you can report a scam, a company or an unwanted call and get next steps, and the FTC says it cannot resolve your individual report; and Citizens Advice in England, Adviceline 0800 144 8848, usually 9am to 5pm, Monday to Friday, which is not available on public holidays. Both are in the Resource Bank and cited below.

Who this is not for. If you rent somewhere that bars car work on the property, one person says a lease can forbid even an oil change, and some people say living in an apartment can rule it out altogether. If you have no driveway or garage, the advice assumes space you may not have. Some people agree that if you cannot physically do the work, you pay for it. If your car is a recent one with a lot of electronics, some people say it is much harder to work on than older cars and risky for a beginner. If you drive an electric car, the overheating page does not cover it: electric cars cool differently. The warranty and used-oil lines are about the United States, and the pages give no brake procedure and no step-by-step for any job; your manual, or a repair manual for your exact model, does that. Nothing here is mechanical advice for your particular car; its manual and a mechanic are. One person says doing your own work only makes sense if your time is worth little to you; some people answer that unless you earn a very high hourly wage, the shop’s labour costs more than your time does. Both are about the same arithmetic, and you are the one who knows what your hours are worth.