Top 5 repairs every car owner should know

Cars go wrong. It's one of the reasons Haynes exists – we're here to help home mechanics fix their vehicles. It doesn't matter how experienced you are, with a Haynes manual in one hand (either as a printed book or an online manual) and suitable tools in the other, you can carry out basic car repairs yourself at home.

What are the easiest car repairs to do yourself? Here are 5 of the most common issues experienced by drivers, followed by possible solutions you can apply with your Haynes manual.

Why won't my car start? Several issues could be to blame for a car not starting, and a few more clues are needed to work out what's going on. Here's how to carry out DIY auto repairs on a car that won't start.

First, can you hear the starter turning when you twist the key in the ignition or press the start button? If there's silence or a clicking noise, there are two likely culprits: the battery or the starter itself. Are other electrical items, such as the interior lights and dashboard instruments working? If not, the battery is likely to be flat or a battery connection could be loose. Use jumper cables and a donor car to get the car started or change the battery.

If the lights are working, the starter is likely to be the issue, either because of a loose wire on the motor or solenoid, or because the unit has simply failed and needs to be replaced.

If the starter is turning the engine, but the latter is failing to spring to life, the following issues could be to blame:

• Fuel tank is empty (check the gauge)
• Battery is low on charge (engine rotates slowly)
• Ignition components damp or damaged
• Broken, loose or disconnected wiring in the ignition circuit
• Worn, faulty or incorrectly gapped spark plugs (petrol engines)
• Fuel injection system fault
• Major mechanical failure (eg, timing belt/chain)
• Air in fuel system (diesel engines)
  

The check engine light looks like the engine block in profile and can be amber or red, and can be on permanently or flash.

What does a flashing check engine light mean? It indicates a mechanical fault with the engine, or a problem with the ECU, the electronic Engine Control Unit. The engine may fail (expensive and potentially dangerous) or the car may enter a limp-home mode that will get you to a place of safety but no more (it usually won't allow the revs to exceed 2000-3000rpm).

A cheap-to-buy OBD scanner can be plugged into the car's OBD port and any stored trouble codes retrieved from the car's computer. Google this and you should be able to narrow down the cause of the check engine light.

Most OBD scanners are capable of wiping the error code(s) from the car's memory once you've cured the issue, which should make the warning light disappear if it hasn't already.

Car noises can be notoriously tricky to trace so it's always helpful to have someone with you to help narrow it down, especially if you need to operate the controls from the driver's seat to recreate the issue.

Is there a noise under the hood? A squealing sound when you start the engine and when you rev it could be a sign of a slipping serpentine belt, often caused by a faulty belt tensioner or the belt itself. This may be accompanied by a red battery light on the dash, either flickering intermittently or on all the time, which indicates that the alternator isn't charging the battery (because of the slipping belt).

Other under-hood noises could be pre-ignition pinking or knocking during acceleration or under load, caused by either an ignition system fault, an incorrect grade of spark plug, a vacuum leak at the throttle body, intake manifold or associated hoses, excessive carbon build-up in engine or a blocked injector/fuel injection system fault.

Whistling or wheezing noises can be caused by a leaking intake manifold or throttle body gasket, exhaust manifold gasket or pipe-to-manifold joint, or a leaking vacuum hose, a blowing cylinder head gasket or a leaking turbocharger/intercooler hose.

Tapping or rattling noises may be made by a worn valve gear or camshaft or an ancillary component fault (coolant pump, alternator, etc). An exhaust system heat shield can also rattle at certain revs when it starts to loosen.

Knocking or thumping noises can be made by worn big-end bearings (regular heavy knocking, perhaps less under load), worn main bearings (rumbling and knocking, perhaps worsening under load), piston slap (most noticeable when cold) or an ancillary component fault (coolant pump, alternator, etc).

Worn out brake pads and discs can result in squealing noises when you're pressing the brake pedal, a loud exhaust note is usually caused by corrosion to the exhaust system while a clicking or knocking noise when you're making tight turns at low speed can be generated by a worn outer constant velocity joint or a lack of constant velocity joint lubricant, possibly due to damaged gaiter.

This is one of the best car repairs to learn as a beginner because it's sadly inevitable that you will end up with at least one puncture during your motoring life.

You should already know if you have a spare wheel and emergency jack in the trunk. If they're there (and you've regularly checked it's inflated!), follow these simple steps:

• Park the vehicle on firm, level ground and chock the wheels that aren't going to be raised off the ground.
• Put the gearbox in Park (automatic) or neutral (manual). Apply the handbrake/paring brake.
• If applicable, any passengers should exit the car and move to a safe area away from the road, even if the weather is poor.
• If you’re changing a wheel, loosen the wheel nuts before you raise the vehicle. It’s dangerous to try to loosen them after the wheel is off the ground.
• Jack points on a car: on some vehicles, you’ll find a notch in the longitudinal seam that protrudes downward below the sill; on others, you’ll find lifting pads on the underside of the vehicle, right behind the front wheel housings and immediately in front of the rear wheel housings. If you can’t locate the designated jacking areas on your vehicle, refer to your owner’s manual.
• Get the jack out of the boot (If you can’t find the jack, refer to your owner’s manual). It's usually beneath the spare wheel, so remove that, too.
• Place the jack in position under the side of the vehicle and closest to the wheel to be changed, and adjust the jack height until it fits between the notches in the sill - or touches the lifting pad.
• Operate the jack with a slow, smooth motion until the wheel is off the ground.
• Remove the wheels nuts by hand, pull off the wheel, install the spare and thread the wheel nuts on with the beveled sides facing in. Tighten them snugly, but wait until the vehicle is lowered to tighten them completely.
• Lower the car to the ground and remove the jack. Don’t forget to tighten the wheel nuts. If possible, tighten them to the specified torque (see your Haynes Manual), in a criss-cross pattern. If you don’t know the torque specification, tighten the wheel nuts securely and have them checked by a service station as soon as you get to the next town.
• If your vehicle is equipped with a space-saver spare wheel, remember that it’s intended only for temporary use until the regular tyre can be repaired. Do not exceed 50 mph while using the temporary spare.

If there's no spare wheel you should have a can of tyre sealant (sometimes called gunk) and maybe a compressor that needs power from a 12V socket. Read the instructions and follow them to the letter (this is just a guide):

• When stationary and safe remove the tyre valve cap and screw the sealant nozzle onto the valve. Pressing the trigger will force a mix of compressed air and sealant into the tyre.
• It may take a little while to fill the tyre, and if you see any latex (usually white) bubbling out of the tyre tread, you know it's working. If the hole is larger than around 3mm, then it's likely the sealant won't work.
• Once sealed and inflated it's important to drive the car straight away to disperse the sealant. Drive slowly (under 50mph) for a couple of miles then check the tyre again.
• If you don't have a tyre compressor, get to a gas station with a tyre inflator, and add more air to the tyre.
• As it's a temporary fix you shouldn't drive over 50mph, or for more than around 100 miles before getting it repaired. Don't forget to buy a new can of sealant to replace the old one! 

This is one of the easiest car repairs to do yourself. We recommend you change your wiper blades once a year. It doesn't matter how often you use them or where you live, because the UV rays and heat from the sun/low winter temperatures do bad things to the silicone.

It's vital that you get the right parts for your model, and a reputable make (Bosch wiper blades, for example, as well as Michelin). Measure yours and look them up online/visit a car parts shop, and verify that the new parts are suitable for your vehicle . You'll often be able to buy blades in pairs for the windshield, even if they're different lengths. Don't forget the blade for the rear screen, if applicable.

Before you remove the old blades, take a close-up photo of where they connect to the arm – this could be useful if the new ones come with a variety of adapters to fit different wiper arms.

Here's some more information on how to change wiper blades, plus a short video.