Summer Car Checklist UK — 10 Checks Before Hot Weather

By Salek Tyre & Mechanic · Ashford, TW15

Cold weather gets all the attention — but summer heat puts its own set of demands on your car. Overheating engines, over-inflated tyres, degraded batteries and a struggling air conditioning system are all more likely in summer. Here are 10 checks to carry out before the temperature rises — most take under five minutes each.

1. Check your coolant level and condition

Your engine cooling system works hardest in summer. The coolant reservoir (a translucent plastic tank near the radiator) has MIN and MAX markers — the level should sit between them when the engine is cold. Never open the cap when the engine is hot.

Check the colour and condition too: coolant should be bright green, blue or pink. Brownish or rusty coolant has degraded and should be flushed and replaced — old coolant loses its anti-corrosion properties and cannot absorb heat as effectively. Most manufacturers recommend a coolant flush every 2–5 years.

2. Check your tyre pressures

Air expands with heat — tyres that are correctly inflated in cold conditions can become over-inflated as temperatures climb. Over-inflated tyres have a smaller contact patch with the road, reducing grip and making the ride harder.

Check pressures in the morning when tyres are cold. The correct pressures for your car (front and rear, often different) are on a sticker inside the driver's door or in your handbook. See our guide on how to check tyre pressure for step-by-step instructions. Also check tread depth — see tyre tread depth UK for the legal minimum.

3. Service or recharge your air conditioning

If you switch the AC on for the first time in summer and the cabin is slow to cool or stays uncomfortably warm, the refrigerant may be low. AC systems lose around 10–15% of their refrigerant per year through normal permeation.

A recharge takes less than an hour and costs £50–£150 depending on your car's refrigerant type. If you recharge every 2 years, performance stays consistent and the compressor stays properly lubricated. See our guide on air conditioning recharge cost in Ashford.

4. Check your engine oil level and grade

High ambient temperatures push engine oil temperatures higher. Oil that is already degraded or low in level will struggle to lubricate effectively at summer temperatures.

Pull the dipstick when the engine is cold, wipe clean, reinsert fully, then pull and read. Oil should sit between the MIN and MAX marks. If it is below MIN, top up with the correct grade (check your handbook). If the oil is black and smells burnt, it is overdue a change. Summer driving is not the time to push the interval.

5. Test your battery

Many people associate flat batteries with winter — but heat is actually a greater enemy of battery longevity. High temperatures accelerate the chemical degradation inside the battery, causing internal damage that only becomes apparent months later when the cold snap arrives.

If your battery is over 3 years old, ask us to test it — a battery health check takes a few minutes and tells you its current capacity versus when it was new. Proactive replacement before it fails avoids a breakdown. See our guide on car battery warning signs.

6. Inspect your wiper blades

UV from summer sun degrades rubber wiper blades faster than any amount of winter use. Blades that smear, streak, or squeak rather than clearing cleanly should be replaced. Modern blades are inexpensive and straightforward to fit — and being caught in a summer downpour with failing wipers is both dangerous and an MOT fail waiting to happen.

7. Check all fluid levels

Beyond coolant and oil, check these before summer driving:

• Brake fluid — absorbs moisture over time; a visual check of the reservoir (MIN/MAX marks) and a fluid change if overdue (every 2 years is typical)
• Power steering fluid — if your car has hydraulic power steering, check the reservoir level
• Screenwash — summer driving brings insects and dusty roads; keep the reservoir topped up. Use a proper screenwash concentrate, not plain water, which can cause legionella in the tank

8. Inspect your tyres for cracks and sidewall damage

UV and heat cause tyre rubber to harden and crack over time — particularly on the sidewalls. Check for small cracks, bulges or bubbles in the sidewall of each tyre. A bulge indicates the internal structure is compromised — the tyre should be replaced immediately as it is at risk of blowout. Sidewall cracks that are more than surface-level also warrant replacement.

If your tyres are over 5 years old, they may need replacing on age grounds even if the tread is still above the legal limit. See our guide on when to replace your tyres.

9. Check your brakes before any long summer journey

Summer road trips put more sustained demands on brakes than everyday town driving. Before a long journey, listen for grinding or squealing when braking and check for any pulling to one side. If anything feels different from normal, get a brake inspection before setting off. A brake inspection is free at our garage.

10. Clean or replace your cabin air filter

The cabin (pollen) filter cleans the air entering the car through the heating and ventilation system. A clogged filter forces the blower to work harder, reduces airflow, worsens air quality inside the car and makes the air conditioning less effective. Summer is a good time to have it changed — it takes 10–15 minutes and is typically replaced at a full service.