European summers seem to be growing hotter with each passing year. Much like we feel the scorching heat ourselves, our vehicles also suffer under the unrelenting sun. While most drivers focus on winterizing their cars, the truth is that heat can inflict even greater damage than cold temperatures. The following problems tend to surface regularly during the summer months:
Fortunately, there are plenty of steps we can take to shield our four-wheelers from warm-weather damage. Some approaches are straightforward — parking in shaded spots, avoiding the peak heat hours of the day, and using car covers. Others call for a bit more attention and upkeep. Regardless of which path you take (ideally, you should follow all of them), your vehicle will be far better equipped to handle the heat than it would have been otherwise.
Below are Valvoline's best recommendations for preparing your car for high temperatures and keeping it in excellent shape throughout the summer.
If we think of a car as a living organism, engine oil is the lifeblood that keeps every component functioning properly. Before modern advancements in lubrication technology, motor oil was highly susceptible to temperature fluctuations, which significantly impacted how freely it moved through the engine. This flow characteristic is known as viscosity — essentially a measure of how thick or thin a liquid is.
In cold conditions, older motor oil would thicken into something resembling molasses, failing to coat engine components adequately. In hot conditions, the same oil would thin out excessively and slide off the parts. The good news, however, is that lubrication science has advanced tremendously, and today we have access to multi-viscosity engine oils. True to their name, these oils adjust their weight in response to temperature — thinning out in the cold and thickening in the heat — so proper lubrication is maintained at all times.
When getting your car ready for hot weather, start by finding out what type of oil it requires. Pick up your engine oil container and read the label. Most manufacturers, Valvoline among them, use two numbers to indicate the weight rating. The first number, followed by the letter "W", represents the winter performance rating. The second, typically higher number reflects the maximum temperature performance per the SAE standard. Take Valvoline 5W-30 engine oil as an example — a multi-grade oil that delivers year-round protection. The "5W" indicates the oil's ability to flow in cold temperatures, while the "30" confirms it remains fluid at the engine's normal operating temperature of 100°C. This oil is therefore well-suited for use across all seasons in most temperate regions.
A failed coolant system is among the most frequent reasons drivers find themselves stranded on the roadside during summer. As the name implies, car coolant regulates your vehicle's temperature and guards against overheating. It also serves several additional functions, including:
Most coolants are composed of two key ingredients — water and antifreeze. Antifreeze stops the coolant from freezing in winter, but it also prevents it from boiling in summer. It contains a compound that lowers the freezing point while simultaneously raising the boiling point, protecting the engine from heat damage. Trusted manufacturers such as Valvoline also incorporate additives into the coolant formulation to guard against rust and corrosion in the heater, radiator, and engine.
Naturally, insufficient coolant will leave your car vulnerable to overheating and engine damage in high temperatures. As part of your summer prep, be sure to inspect your coolant levels. Locating the coolant reservoir under the bonnet is straightforward — simply open it and check where the fluid sits. If it falls below the marked line, top it up with the correct car coolant and you're good to go.
You may be asking yourself, "Which coolant is right for my vehicle?" In most cases, a multi-vehicle coolant is the ideal choice, as it suits passenger cars, motorcycles, light commercial vehicles, and even boats. It works across all seasons, so it won't create any complications for the user. For additional guidance on diesel engine coolant selection or any other fluid-related queries, our Lubricant Advisor can point you toward the right coolant and lubricant for your specific vehicle.
Tyres demand attention regardless of the season, but the transition from cold to warm weather presents an ideal opportunity to make sure your wheels are in proper shape. If your vehicle is running on winter tyres, swapping them for summer or at minimum all-season tyres is essential. Summer and all-season tyres are constructed from harder compounds that handle hot asphalt far more effectively than winter tyres. When swapping your tyres, it's also worth rotating them — moving the front tyres to the rear and vice versa. This well-established technique helps even out tyre wear, improves fuel efficiency, and enhances overall vehicle performance in warm conditions.
You should also keep a close eye on tyre inflation at all times. Intense heat can cause tyres to lose pressure more rapidly than normal, increasing the risk of a blowout and raising fuel consumption. Fortunately, routine pressure checks as warmer weather arrives can prevent this entirely. Each vehicle has a recommended pressure level, which can be found in the owner's manual or on the sticker near the driver's door. To measure pressure, use a tyre pressure gauge, or stop by a garage or petrol station and use the air compressor. If the pressure reads low, add air until the gauge shows the appropriate level.
In addition to pressure, tread depth deserves attention as well. Heat accelerates tread wear, so measuring yours is a wise precaution. Across Europe, the legal minimum tread depth stands at 1.6 mm. That said, most experts and tyre manufacturers advise replacing tyres once tread depth drops to 2 mm. The recommended depth is 3 mm or more, with 4 mm being the standard for winter tyres. You can measure tread depth with a dedicated gauge, or conduct a visual check. Some tyres feature raised wear indicators embedded in the tread grooves — if these are flush with the tyre surface, it's time to start shopping for replacements.
Like any battery, a car battery does not respond well to extreme heat. While your engine may fire up more easily in hot weather, that doesn't mean the battery is thriving. Intense heat can cause the battery to off-gas more than normal, which corrodes the terminals and depletes the electrolytes — often resulting in premature battery failure.
If your vehicle has been exposed to extreme heat, or if your battery is several years old, have it tested. Replace the battery if its amperage falls below normal, or if the casing appears distorted or swollen. Look for any bumps on the housing along with corrosion and signs of leakage if a full diagnostic isn't available.
Leaks can be cleaned using distilled water, though consulting a professional and having the battery properly tested is always the safer option. A thorough test will confirm whether the battery is still performing adequately. Skipping this step could leave you struggling to start the car — or facing a complete breakdown.
Car interiors can reach temperatures that make driving without air conditioning completely unbearable. Before switching on the AC, though, it's worth confirming that the system is in good working order. Checking your AC at home is difficult, but a short visit to a garage will allow a technician to assess the cooling system and ensure you stay comfortable throughout the summer.
Your AC may also require regassing. This procedure involves evacuating the old gas and recharging the system with fresh refrigerant. Over time, this cooling gas naturally escapes, reducing the AC's effectiveness. A quick and cost-effective regassing will restore the system to its original performance.
Throughout winter and the rest of the year, your filters accumulate dust and debris, blocking fresh air from reaching the engine and the cabin. This buildup can negatively impact engine performance, fuel economy, and even your personal health. It is generally recommended that drivers replace their filters every 12 months or 20,000 kilometres — and even more frequently in hot climates.
Higher temperatures bring increased humidity, and moist air can accelerate filter clogging. If you live in a particularly humid region or are planning a road trip to one, replacing the filter beforehand is a sensible precaution. Allergy sufferers know all too well how miserable a long drive can be when allergens are continuously recirculated throughout the cabin.
Heavier use of the AC can also trigger the need for an earlier-than-usual filter replacement. The AC draws in hot outside air, passes it through the filter to cool it, and then releases it into the cabin. This repeated cycling causes clogging over time, so if your air conditioning seems less powerful than before, the air filter may well be the culprit.
Fortunately, replacing filters is a quick and easy job that many drivers can handle at home. Both engine air filters and cabin air filters can typically be swapped out in under 10 minutes — just watch a few how-to videos and familiarise yourself with where the filters are located in your specific vehicle.
If summer doesn't bring much rain where you live, you might question why wipers are even worth mentioning. But wipers aren't just for rainfall — in many regions, summers are dusty, and these blades are invaluable for sweeping blinding sand and grit from the windscreen. Furthermore, since wiper blades are made of rubber, sun exposure can degrade them, making them more of a nuisance than a help.
Inspect your current wiper blades to confirm they're fit for purpose in the months ahead. If they show any signs of cracking, folding, or other deterioration, replace them. While you're tending to the windscreen, take a moment to look under the bonnet and top up the windshield washer fluid. This is a simple task — locate the reservoir (typically transparent and marked with a washer fluid symbol on the cap) and fill it with your preferred washer fluid rather than plain water. Even winter formulas containing antifreeze are superior to water, as they remove insects and grime more effectively and won't leave streaks.
We may all look forward to sunshine and warm days, but our cars have a different perspective. Preparing our vehicles for summer is just as important as winterizing them — and this is especially true before a summer road trip, since a breakdown in the middle of your journey can derail your plans entirely.
Beyond the measures outlined above, it's also a good idea to keep a stock of essential fluids on hand at all times. This means carrying spare car coolant, windscreen washer fluid, and a quality engine oil. All of these products are available from Valvoline, helping you stay safe and prepared no matter the season. Our engine oils, car coolants, and other fluids are true essentials for any summer drive, particularly in extreme heat. Have a great summer with Valvoline!