Common Car Problems You Can Fix Yourself (And When to Call a Mechanic)

Summary

• Easy DIY fixes: Flat battery, changing a tyre, wiper blades, bulbs, and fluid top-ups are all doable at home.
• Basic tools: A socket set, screwdrivers, jump leads, and a tyre inflator will handle most minor jobs.
• Know your limits: Brakes, suspension, and anything involving airbags or complex electronics should go to a professional.
• Save money: Simple DIY maintenance can save you hundreds of pounds a year.

Not every car problem needs a trip to the garage. Many common issues have simple fixes you can do yourself with basic tools and a bit of confidence.

This guide covers the most common car problems, how to fix them yourself, and when you should call in a professional.

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Flat Battery: How to Jump Start Your Car

A flat battery is one of the most common breakdowns. If your car won't start and you hear a clicking sound, the battery is likely dead.

What You Need

• Jump leads (carry these in your boot)
• A working car with a charged battery

How to Jump Start

1. Park the working car close to yours, bonnet to bonnet
2. Turn off both engines and all electrics
3. Connect the red lead to the positive (+) terminal on the dead battery
4. Connect the other end of the red lead to the positive (+) on the good battery
5. Connect the black lead to the negative (-) on the good battery
6. Connect the other end of the black lead to an unpainted metal surface on the dead car (like an engine bolt) - NOT the battery
7. Start the working car and let it run for a few minutes
8. Try starting your car
9. Once running, remove leads in reverse order (black first)
10. Drive for at least 20 minutes to recharge the battery

When to get help: If the battery keeps going flat, it may need replacing. If it's relatively new, there could be a drain from faulty electrics. See our car battery guide for more.

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Changing a Flat Tyre

Every driver should know how to change a tyre. It's straightforward once you've done it once.

What You Need

• Spare tyre (check it's properly inflated)
• Jack (usually in the boot)
• Wheel brace/wrench
• Locking wheel nut key (if fitted)

How to Change a Tyre

1. Pull over somewhere safe and flat. Turn on hazards.
2. Apply the handbrake and put the car in gear (or Park for automatics)
3. Loosen the wheel nuts slightly while the tyre is still on the ground
4. Position the jack under the reinforced jacking point (check your manual)
5. Raise the car until the flat tyre is off the ground
6. Remove the wheel nuts and take off the flat tyre
7. Put on the spare and hand-tighten the nuts
8. Lower the car and tighten the nuts fully in a star pattern
9. Check the spare's pressure at the next opportunity

For a detailed guide, see how to change a tyre.

Space savers: If you have a space-saver spare, don't drive over 50mph and replace it with a full-size tyre as soon as possible.

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Replacing Wiper Blades

Worn wipers that streak or smear are an easy fix and will help you pass your MOT.

How to Replace Wipers

1. Lift the wiper arm away from the windscreen
2. Find the release mechanism (usually a small tab or button)
3. Slide the old blade off
4. Slide the new blade on until it clicks
5. Lower the arm gently back to the screen

Wipers cost £10-30 for a pair from any motor factor or online. It takes 5 minutes to fit them.

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Replacing Light Bulbs

A blown bulb is an instant MOT fail and can earn you a police fine. Luckily, most are easy to replace.

How to Replace a Headlight Bulb

1. Open the bonnet and locate the back of the headlight unit
2. Disconnect the wiring connector
3. Remove the dust cap (if fitted)
4. Release the clip or twist-lock holding the bulb
5. Remove the old bulb (don't touch the glass of halogen bulbs with bare fingers)
6. Insert the new bulb and secure it
7. Reconnect the wiring and replace the dust cap
8. Test the light

Brake lights and indicators are usually accessed from inside the boot or behind panels. Check your owner's manual for specifics.

Tip: Replace bulbs in pairs. If one has blown, the other is likely to follow soon.

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Topping Up Fluids

Checking and topping up fluids is basic maintenance that prevents breakdowns.

Engine Oil

1. Park on level ground with the engine cold
2. Pull out the dipstick, wipe it clean, reinsert fully, then remove again
3. Oil should be between the min and max marks
4. Top up through the oil filler cap if low - use the correct grade

Coolant

• Check the expansion tank when cold - level should be between min and max
• Never open the cap when hot - serious burn risk
• Top up with the correct coolant type (check your manual)

Washer Fluid

• Find the washer reservoir (usually has a windscreen symbol on the cap)
• Top up with screenwash (not just water, which can freeze)

Brake Fluid

• Check the level in the reservoir under the bonnet
• If it's low, top up with the correct DOT-rated fluid
• If it drops quickly, there may be a leak - see a mechanic

For a full guide, see our car maintenance checklist.

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Fixing Minor Scratches

Light scratches that haven't gone through to bare metal can often be polished out or touched up.

For Light Scratches

1. Wash and dry the area
2. Apply a cutting compound with a microfibre cloth
3. Polish in circular motions
4. Wipe off residue and apply wax

For Deeper Scratches

1. Clean the area thoroughly
2. Apply touch-up paint (matched to your car's colour code)
3. Let it dry completely
4. Apply clear coat if included
5. Polish the area once cured

For more detail, see our guide to car detailing.

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When to Call a Mechanic

Some jobs are best left to professionals. Call a mechanic if:

• Brakes: Any brake work beyond checking pads should be done by a pro
• Suspension: Springs, shocks, and bushes require specialist tools
• Airbags: Never DIY - they're explosive and dangerous
• Fuel system: Fire risk if done incorrectly
• Timing belt: Get it wrong and you'll destroy the engine
• Electrical issues: Complex diagnostics need proper equipment
• Warning lights: Get them diagnosed before they become expensive
• You're not confident: It's okay to admit a job is beyond your skills

Safety first: If a job involves jacking the car up, always use axle stands as well as a jack. Never rely on the jack alone.

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Basic Tool Kit for Your Car

Having these items in your boot will help you handle most roadside emergencies:

• Jump leads
• Tyre inflator/compressor
• Tyre depth gauge
• Torch (with fresh batteries)
• Socket set and spanners
• Screwdrivers (flat and Phillips)
• Pliers
• Duct tape and cable ties
• Spare bulbs and fuses
• Engine oil (1 litre of correct grade)
• Screenwash
• Old towel or rag
• High-vis jacket and warning triangle

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Common Questions

Will DIY repairs void my warranty?

Basic maintenance like oil changes, wiper blades, and bulb replacements generally won't affect your warranty. However, more involved work might. Check your warranty terms.

Where can I learn more about car repairs?

YouTube has excellent tutorials for most makes and models. Haynes manuals are also a great resource for your specific car.

How do I find the right parts for my car?

Enter your registration on sites like Euro Car Parts, Halfords, or GSF Car Parts to find compatible parts for your exact vehicle.

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Final Thoughts

Learning basic car maintenance and repairs saves money and keeps you safe on the road. Start with the simple stuff - changing a tyre, topping up fluids, replacing wipers and bulbs.

As your confidence grows, you can tackle more. But always know your limits. Some jobs are best left to the professionals.

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