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19 Worst Car Tips Mechanics Have Ever Heard

Every driver has heard their fair share of car tips and tricks, but not all advice is created equal. Mechanics, the unsung heroes of the automotive world, have seen it all. They’ve encountered car owners armed with well-meaning but ultimately disastrous advice that can turn a simple maintenance task into a costly catastrophe.

Using Dish Soap for a Cheaper Clean: A Costly Mistake

dawn dish soap
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When it comes to washing your car, using dish soap might seem like a budget-friendly alternative to specialized car wash soap. However, this is a common misconception that can lead to unintended consequences. Dish soap is designed to cut through grease and remove tough stains from dishes, but it can be too harsh for your car’s paint. Unlike dedicated car wash soaps, which are formulated to clean without stripping away the protective wax layer, dish soap can strip away the wax and leave your car’s finish vulnerable to damage from UV rays, contaminants, and the elements. It’s essential to invest in a quality car wash soap to maintain the appearance and longevity of your vehicle’s paint.

Idling Your Engine: A Misguided Effort to Keep Warm

Car driver starting the engine Start, stop engine button.
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During cold weather, many people believe that idling their car’s engine for extended periods is the best way to keep it warm and prevent damage. However, this is a myth that can waste fuel, increase emissions, and harm your engine over time. Modern engines are designed to warm up quickly, and idling for more than a minute or two is unnecessary. In fact, excessive idling can lead to carbon buildup on engine components, decrease fuel efficiency, and contribute to air pollution. To warm up your car efficiently in cold weather, it’s better to drive gently and allow the engine to warm up naturally while in motion.

Skipping Oil Changes: A Risky Move

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Some car owners believe that changing the oil in their vehicle is an unnecessary expense, often dismissing it as a tactic by mechanics to make money. This couldn’t be further from the truth. Regular oil changes are vital to the health and longevity of your engine. Engine oil lubricates critical components, reduces friction, and helps dissipate heat. Over time, oil breaks down, becomes contaminated, and loses its effectiveness. Skipping oil changes can lead to increased engine wear, reduced fuel efficiency, and eventually costly engine damage. Follow your vehicle manufacturer’s recommended oil change intervals to keep your engine running smoothly and avoid costly repairs down the road.

Neglecting Tire Rotations: A Time-Saving Mistake

High performance all season tires design for modern sports car both highway & track combining safety, stability, handling and grip,
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Tire maintenance is often overlooked, and some car owners believe that rotating tires is a waste of time. However, neglecting tire rotations can result in uneven tire wear and affect your vehicle’s handling and safety. Tires on the front and rear of a car wear differently due to variations in weight distribution and steering forces. Rotating your tires at regular intervals ensures that they wear evenly, extending their lifespan and improving overall performance. It also helps maintain proper wheel alignment, which can prevent issues like uneven tire wear, reduced fuel efficiency, and a rough ride. Don’t dismiss tire rotations; they’re a crucial part of car maintenance.

Redlining Your Engine: A Performance Myth

V8-6-4 Engine
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The idea that redlining your engine occasionally can improve its performance is a misconception that can lead to severe engine damage. Redlining refers to pushing the engine to its maximum RPM (revolutions per minute), which is marked by a red zone on the tachometer. While high-performance vehicles are designed to handle occasional high RPMs, regularly redlining a standard car’s engine can cause excessive stress and wear. It can lead to premature engine failure, increased maintenance costs, and decreased fuel efficiency. To maintain your engine’s performance and longevity, it’s best to drive within the recommended RPM range specified in your vehicle’s owner’s manual.

Topping Off Your Gas Tank: A Common Misconception

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The belief that topping off your gas tank is essential to avoid running out of fuel is a widespread but misguided practice. In reality, it’s not necessary and can even be detrimental to your vehicle. Modern fuel pumps are designed to automatically shut off when your tank is full, preventing overfilling. Attempting to squeeze in extra fuel after the pump stops can lead to fuel spillage, damage to the evaporative emissions system, and potential harm to the environment. It’s best to stop refueling when the pump clicks off, as this is an indication that your tank is adequately filled.

Ignoring Dashboard Warning Lights: A Risky Assumption

Many different car dashboard lights with warning lamps illuminated.
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Dashboard warning lights are your car’s way of communicating potential issues or malfunctions. Ignoring them and assuming they will go away on their own is a risky and costly assumption. Warning lights can signal problems with the engine, brakes, transmission, and more. Ignoring these indicators can lead to more significant and expensive repairs down the road. It’s essential to address warning lights promptly by having your vehicle diagnosed and repaired by a qualified mechanic to prevent further damage and ensure your safety on the road.

Overinflating Tires: Not the Path to Fuel Efficiency

Flat Tire Replacing Closeup Photo. New Tire For the Modern Vehicle.
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While it may seem logical to overinflate your tires to improve fuel efficiency, this practice can have adverse effects on your vehicle’s handling and safety. Overinflated tires can result in a harsh, uncomfortable ride and reduced traction, especially on wet or slippery surfaces. It can also lead to uneven tire wear, increasing the risk of blowouts. To maintain proper tire pressure and maximize fuel efficiency, it’s crucial to follow the manufacturer’s recommended tire pressure specifications, which can usually be found on a sticker inside the driver’s door jamb or in the owner’s manual.

Frequent Engine Revving: Not the Key to Top Shape

car gas pedal
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The notion that regularly revving your engine keeps it in top shape is a common misconception. Modern engines are designed to operate efficiently within a specific RPM range, and excessive revving can cause unnecessary wear and tear. Frequent high RPMs can lead to increased engine stress, overheating, and accelerated component wear. It’s best to drive your car within the recommended RPM range for normal driving conditions and avoid unnecessary high-revving, which can lead to reduced engine lifespan and higher maintenance costs.

Premium Fuel in a Regular Car: A Costly Myth

Gas pump at an American gas station with a black nozzle and colorful fuel option buttons oil petrol gasoline
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Using premium fuel in a regular car, one that doesn’t require it, is a prevalent but costly myth. Premium fuel has a higher octane rating, which is essential for high-performance and turbocharged engines that require it. However, using premium fuel in a standard, non-high-performance vehicle won’t improve its performance or fuel efficiency. It’s a waste of money and won’t provide any noticeable benefits. Stick to the fuel grade recommended in your vehicle’s owner’s manual for optimal performance and cost-effectiveness. Using the right fuel for your car is more important than using a higher octane rating.

Using Water Instead of Coolant: A Recipe for Engine Trouble

Tesla Battery Coolant
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Believing that a car can run just fine on water instead of coolant is a dangerous misconception. Coolant, often referred to as antifreeze, serves a crucial role in regulating your engine’s temperature and preventing it from freezing or overheating. Water alone cannot provide the same level of protection. In extreme cold, water can freeze and cause engine block damage, while in high temperatures, it can lead to overheating and engine failure. Always use the recommended coolant mixture specified in your vehicle’s owner’s manual to maintain proper engine temperature and prevent costly repairs.

Neglecting Car Washes: A Myth About Dirt Protection

car wash
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The idea that never washing your car can protect its paint is a fallacy. While it’s true that dirt and debris can act as a temporary barrier against minor scratches, allowing dirt to accumulate on your car’s surface can lead to more significant damage over time. Dust and contaminants can wear down the protective clear coat and paint, leading to premature paint fading and corrosion. Regular car washing and waxing are essential for preserving your vehicle’s appearance and protecting its paint from long-term damage.

Disconnecting Your Car Battery: A Misunderstanding About Energy Savings

Man throwing old empty car battery in garbage disposal with recycling symbol
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Some believe that disconnecting their car battery when the vehicle is not in use can save energy and extend the battery’s lifespan. However, this practice is unnecessary and can lead to unintended consequences. Modern cars are equipped with systems that draw a small amount of power when not in use, such as for memory functions and security systems. Disconnecting the battery can disrupt these systems, lead to issues with reprogramming, and even result in the loss of certain settings. Instead, regularly drive your car to keep the battery charged or consider using a trickle charger if it will be idle for an extended period.

Warming Up Your Car by Revving: A Cold Weather Myth

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On cold winter mornings, some drivers believe that starting the car and immediately revving the engine will warm it up more quickly. However, this is counterproductive and can potentially harm your engine. Modern engines are designed to warm up efficiently during regular driving. Excessively revving your engine can lead to increased fuel consumption, unnecessary wear on engine components, and increased emissions. It’s better to start your car, allow it to idle briefly, and then drive gently to let the engine warm up naturally while minimizing wear and tear.

Driving with Windows Down to Save Fuel: A Misguided Belief

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The belief that driving with your windows down to save fuel and avoid using air conditioning is a common misconception. In reality, driving with open windows can decrease your vehicle’s fuel efficiency. When driving at highway speeds with windows down, it creates aerodynamic drag, which can increase fuel consumption and reduce your vehicle’s overall efficiency. In contrast, using air conditioning in a modern vehicle typically has a more modest impact on fuel efficiency. To optimize fuel economy, it’s often more effective to use the air conditioning sparingly and drive with windows up, especially at higher speeds.

Replacing Only One Damaged Tire: A Misconception About Cost-Effectiveness

Finger pointing to damage on tire tread. Tire tread problems by tire pressure improper, Wheel alignment
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The notion that replacing only one damaged tire is more cost-effective is a common myth that can lead to safety hazards and uneven tire wear. Tires on a vehicle should ideally be of the same brand, model, size, and have similar tread depth to ensure even performance and handling. Mixing different tires can result in poor traction, reduced handling stability, and even unsafe driving conditions, especially in wet or slippery conditions. It’s crucial to replace tires in pairs (either both front or both rear) or, ideally, all four tires at the same time to maintain your vehicle’s safety and handling characteristics.

DIY Brake Pad Replacements: A Risky Assumption

cropped view of mechanic holding brake pad near assembled disc brakes
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While DIY car maintenance can be rewarding, assuming that brake pad replacements are easy and safe for anyone is a dangerous misconception. Brake systems are critical to your vehicle’s safety, and improper brake pad installation or maintenance can lead to brake failure and accidents. Replacing brake pads requires proper tools, knowledge of the braking system, and attention to detail. It’s a job best left to experienced mechanics who can ensure that your brakes function correctly and keep you safe on the road. Attempting DIY brake pad replacements without the necessary expertise can put you and others at risk.

Using Cooking Oil as Engine Lubricant: A Recipe for Disaster

Cooking oil
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Pouring used cooking oil into your engine in an attempt to lubricate it is a misguided and harmful practice. Engines require specialized motor oil to provide proper lubrication, reduce friction, and dissipate heat. Cooking oil is not formulated for the high-temperature, high-stress conditions within an engine. Using cooking oil can lead to engine damage, increased wear and tear, and eventually costly repairs. Always use the manufacturer-recommended motor oil specified in your vehicle’s owner’s manual to maintain engine health and performance.

Fixing a Cracked Windshield with Duct Tape: A Temporary Fix at Best

Female feet on a car dashboard by the windshield. Road trip concept.
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Attempting to fix a cracked windshield with duct tape is a common DIY approach, but it’s far from a proper solution. Duct tape might temporarily hold the glass together, preventing further spreading of the crack, but it doesn’t address the underlying structural issues or ensure visibility and safety while driving. A cracked windshield can compromise the structural integrity of your vehicle, and relying on duct tape is not a safe or effective long-term solution. Instead, seek professional windshield repair or replacement to ensure your safety and maintain the integrity of your vehicle’s structure.

Author: Madison Cates

Title: Managing Editor


Research journalist, Freelance writer, Managing editor

  • Expertise: automotive content, trending topics.
  • Education: LeTourneau University, Bachelors of Science in Business Administration.
  • Over 400 articles and short news pieces published across the web.

Experience: Madison Cates is a journalist located in the great state of Texas. She began writing over eight years ago. Her first major research piece was published by the Journal of Business and Economics in 2018. After growing up in a household of eight brothers and a dad who was always restoring old Camaros, she naturally pivoted her freelance career into the automotive industry. There, she found her passion. Her experience paved the way for her to work with multiple large corporations in automotive news and trending topics. Now, she now finds her home at Wealth of Geeks where she proudly serves as Managing Editor of Autos. Madison is always down to geek out over the latest beautiful cars on the market, and she enjoys providing her readers with tips to make car ownership easier and more enjoyable.

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