When to Replace Common Car Parts
Last updated: February 2026 · 8 min read
Replacing worn parts on schedule is the cheapest form of car maintenance — it's always less expensive than the damage that a failed part causes. This guide covers the most commonly replaced parts on UK cars, with realistic intervals and warning signs to watch for.
🛢️ Engine Oil & Oil Filter
Interval: Every 10,000–20,000 miles or 12–24 months, whichever comes first. Check your handbook — longlife oil intervals are longer but require specific synthetic oils. If in doubt, changing annually is good practice.
Warning signs: Dark, gritty oil on the dipstick. Oil level dropping between changes. Engine noise increasing. Oil pressure warning light.
🌬️ Air Filter
Interval: Every 15,000–30,000 miles or at every major service. More frequently if you drive on dusty roads or in heavy traffic.
Warning signs: Reduced fuel economy. Sluggish acceleration. Engine misfires. Visibly dirty or clogged filter when you inspect it (it should be off-white or light grey, not black).
⛽ Fuel Filter
Interval: Every 20,000–40,000 miles for diesel engines (critical — dirty diesel fuel can destroy injectors costing thousands). Petrol fuel filters often last the life of the car on modern vehicles but should be checked at major services.
Warning signs: Difficulty starting. Engine hesitation or stumbling under acceleration. Loss of power, especially uphill or under load. Engine cutting out.
🛞 Brake Pads
Interval: Every 25,000–60,000 miles depending on driving style. City driving wears pads much faster than motorway cruising. Front pads wear faster than rears (typically 2:1 ratio).
Warning signs: Squealing or squeaking when braking. Grinding noise (urgent — metal on metal). Car pulling to one side. Brake pedal feels soft. Dashboard warning light. Visible pad thickness under 3mm.
💿 Brake Discs
Interval: Every 50,000–80,000 miles, or every 2–3 sets of brake pads. Check thickness against the minimum stamped on the disc.
Warning signs: Visible lip on the outer edge. Deep score marks or grooves. Vibration or pulsing through the brake pedal (warped disc). Blue discolouration (overheating).
🔋 Battery
Interval: Every 4–6 years. Test annually from age 3+, especially before winter.
Warning signs: Slow cranking when starting. Dimming headlights at idle. Electrical glitches. Battery warning light. Needing a jump start. Swollen or leaking battery case.
🌧️ Wiper Blades
Interval: Every 12 months. Replace before winter for best visibility.
Warning signs: Streaking. Smearing. Squeaking. Juddering or chattering. Missed areas. Visible cracks or tears in the rubber.
⚡ Spark Plugs
Interval: Standard copper plugs every 20,000–30,000 miles. Iridium or platinum plugs every 60,000–100,000 miles. Check your handbook — modern engines with longlife plugs often specify 60,000+ miles.
Warning signs: Engine misfiring. Rough idle. Poor fuel economy. Difficulty starting. Failed emissions test. Check engine light.
🔗 Timing Belt / Cambelt
Interval: Every 40,000–100,000 miles or 4–5 years, whichever comes first. This varies hugely by engine — always check your manufacturer's specification. A snapped timing belt on an interference engine destroys the engine, costing thousands. This is the single most important scheduled replacement on your car.
Warning signs: Usually none — timing belts fail without warning, which is why scheduled replacement is critical. Occasionally a ticking noise from the engine cover or slight roughness at idle.
🏎️ Clutch
Interval: No set interval — depends heavily on driving style. Typically 60,000–100,000 miles. City driving and towing wear clutches faster.
Warning signs: Clutch slipping (engine revs rise without corresponding acceleration, especially in higher gears). High biting point. Difficulty engaging gears. Burning smell. Juddering on pull-away.
A Note on Service Schedules
Your car's manufacturer service schedule is the best starting point for replacement intervals. It's designed for your specific engine and takes into account the typical UK driving conditions. You'll find it in your owner's manual or on the manufacturer's website. If you've lost the manual, a quick search for your car's make, model and year plus "service schedule" will usually find it.
Keep in mind that manufacturer intervals sometimes assume ideal conditions. If you do lots of short trips, drive in heavy traffic, tow a caravan, or drive on dusty roads, consider shortening the intervals for wear items like oil, filters, and brake pads.
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