10 harmful misconceptions about car maintenance

Many people, including friends, family, and car manufacturers, offer advice on fuel efficiency, engine performance, and overall vehicle lifespan. However, not all advice is accurate. Here are 10 common misconceptions about car maintenance.
1. You need to change the oil every 3,000 miles (4,800 km) your car has driven.

According to automotive experts, this was only true in the past, but many oil companies and oil shops still promote this idea. Now, most cars manufactured within the last decade only need an oil change every 5,000-7,500 miles (8,000-12,000 km), depending on the manufacturer.

Modern cars have better chemical compositions, widely use synthetic oils, and superior engine designs that reduce the frequency of oil changes. Oil change schedules should only be based on the owner's manual. Otherwise, you'll just be wasting money.

2. Premium fuel is better for the vehicle and increases performance.

This is only true for vehicles equipped with high-compression and high-performance engines. For passenger cars, regular gasoline will still work fine. The cheaper 86-octane fuel still has to meet quality standards, so it won't harm the engine.

Sports cars typically use higher-octane fuels that include detergents and protective agents to keep the turbocharged engine in better condition. Regular gasoline is suitable for mid-range cars.

3. Having your vehicle serviced at unauthorized repair shops will void your warranty.

The vehicle warranty is valid until its expiration date, regardless of where you have your vehicle serviced. Authorized dealerships prefer that vehicle owners only go to them, but it's not mandatory.

Maintenance for vehicles still under warranty can be done at any auto repair shop. All you need to do is keep the receipts to prove what maintenance was done and how much it cost.

4. Warm up the engine before driving in cold weather.

Engine components need to warm up to function properly, but modern engines heat up much faster while you're actually driving. Additionally, bearings and transmissions only fully heat up when the vehicle is in motion.

Therefore, idling the engine a while before driving in cold weather offers no benefit other than making the interior of the car warmer. Fuel consumption and performance are only affected through usage. Thus, idling is essentially a waste of money and fuel.

5. You should replace all four tires at the same time.

In fact, car owners only need to replace individual tires when necessary, as long as they are the same brand, model, and size. To maximize their lifespan, simply ensure that the tires are removed at each oil change.

Additionally, you don't necessarily need to buy new tires if you get a flat. Simply patching it is sufficient because the patches will prevent moisture from entering the steel rim and restore the tire's seal.

6. Wash the car with laundry soap or dish soap.

At first glance, this might seem like a good way to save money. However, washing your car with laundry soap or dish soap actually damages the car's wax finish.

Instead of contributing to rust, pay a little extra for a specialized car wash fluid designed not to damage your car's protective wax coating.

7. The battery will recharge after a short period of driving.

It takes many hours of driving to fully charge a car battery, especially in cold weather. Car accessories like heated seats, radios, and lights draw a lot of power from the alternator. Therefore, even short drives can cause the battery to run out the next time you drive.

8. The transmission fluid should be changed every 50,000 miles (80,000 km).

Although customers are often advised to change transmission fluid every 80,000 km, most modern vehicles use transmission fluid with a longer lifespan. Modern fluids are designed to last up to 160,000 km or even the entire lifespan of the vehicle. This can vary between models, so always refer to your vehicle manufacturer's manual.

9. Open the windows instead of using the air conditioner to save more fuel.

In reality, rolling down the windows or turning on the air conditioner makes very little difference in fuel savings. Turning on the air conditioner consumes fuel faster, that's true. However, opening the windows also increases wind resistance.

Therefore, the car will need to burn a little more fuel to compensate for the disrupted aerodynamic design. The overall impact of opening windows or turning on the air conditioning on fuel economy is minimal. Neither option really offers a greater benefit.

10. Filling up with gas in the morning helps save money on fuel.

Gasoline expands with heat, so many people still believe that filling up with warmer fuel means the car will get less fuel. In theory, fuel pumped in the morning is cooler, allowing for more fuel to be dispensed at a lower cost.

However, that's not actually true. Gasoline is typically stored underground and isolated from temperature changes. Therefore, the time of day you refuel doesn't actually make a difference to the amount of fuel you receive.