Gas is expensive, and filling up with premium gas in San Carlos can cost well over four dollars per gallon. Fortunately, regular unleaded gas works well in most vehicles. However, if an automaker requires premium gas, failing to use it can cause serious engine damage. Here’s why it’s critical to follow the manufacturer’s fuel guidelines.
Understanding the Octane Difference 
The key difference between regular and premium fuels is the octane rating. When gas and air ignite before they should, an explosion called a pre-ignition occurs, causing a knocking sound in the engine. Fuel is given an octane rating based on how well it resists pre-ignition. Premium gas, typically rated at 90 or above, is less prone to pre-ignition and contains additives that help engines run cleanly.
Required vs. Recommend Fuel
Some owner’s manuals “require” premium fuel, while others “recommend” it. Though this may seem like a semantic difference, some vehicles require premium fuel to run smoothly. Others cars may be fine without it. When premium fuel is only recommended, drivers can start with regular fuel and evaluate vehicle performance. If the vehicle experiences decreased fuel economy, performance decline, or engine knocking, it’s time to switch to a higher grade.
Why Is Premium Sometimes Required?
Manufacturers that require premium gas aren’t trying to line the pockets of gas companies. Vehicles with premium gas requirements have fuel systems designed to work with higher octane gas only. With regular gas, drivers may hear a knocking noise from the engine, caused by pre-ignition. If these loud noises are heard, a mechanic should evaluate the vehicle as soon as possible to avoid further engine damage. Filling up with the wrong type of fuel can save money in the short term, but it can also void a vehicle’s warranty and cause damage that requires extensive engine repairs.
Schedule a Car Maintenance Appointment
While premium gas can be costly, failing to follow your manufacturer’s fuel requirements can result in engine damage, decreased fuel efficiency, and decreased vehicle performance. If you’re hearing a knocking sound in your engine, visit A+ Japanese Auto Repair Inc. We have over 20 years of experience providing a wide range of maintenance services for Japanese cars. Our team can even pick up your car to start working on it as soon as possible. Call us today at (650) 595-2277 or fill our convenient form to schedule a maintenance appointment.