What grade of gasoline should be used for Toyota Avalon?
2 Answers
Toyota Avalon should use 92-octane gasoline, as recommended in the vehicle's official user manual. In addition to checking the appropriate gasoline grade in the user manual, you can also find it on the fuel tank cap, which will be clearly marked. Generally, the gasoline grade can also be determined based on the engine's compression ratio. Vehicles with an engine compression ratio between 8.6-9.9 should use 92-octane gasoline, while those with a compression ratio between 10.0-11.5 should use 95-octane gasoline. If the compression ratio is higher, 98-octane gasoline is recommended. However, with the use of new technologies, the compression ratio alone cannot determine the gasoline grade, as high-compression engines can also be tuned to use lower-octane gasoline. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. 92-octane gasoline contains 92% isooctane and 8% n-heptane, while 95-octane gasoline contains 95% isooctane and 5% n-heptane. If you occasionally use the wrong gasoline grade for Toyota Avalon, simply switch back to the correct grade after refueling. However, long-term use of the wrong gasoline grade may have the following effects: For vehicles recommended to use lower-octane gasoline, using higher-octane gasoline will not cause damage, but the increased octane number may alter the fuel's ignition point, leading to delayed combustion in the engine. This reduces the engine's power output and thermal efficiency, resulting in poorer performance. For vehicles recommended to use higher-octane gasoline, using lower-octane gasoline may cause engine knocking. Due to the significantly lower octane number, the gasoline's ignition point decreases, causing premature ignition during the compression stroke. If combustion occurs before the spark plug ignites, resistance will arise during the upward stroke. This resistance makes the engine run very unstably. Mild knocking may only increase noise without significant engine damage, but severe knocking indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and even cylinder scoring in severe cases.
Driving a Toyota Avalon, I've always found that using 92 octane fuel works just fine. It's quite fuel-efficient for city driving, and a full tank can last for a good number of kilometers. Once, I tried using lower-grade 90 octane fuel, and the engine started knocking, the noise increased, and it even shook a bit when I turned on the AC after parking. Later, I looked it up and found that fuel with too low an octane rating can cause knocking and damage the engine, so now I stick to 92 octane. As for 95 octane, it's significantly more expensive without a noticeable performance boost, unless you're doing long-distance driving or climbing steep hills. I recommend checking your owner's manual—it likely suggests using 92 octane or higher for peace of mind. Regular maintenance checks on fuel quality can help prevent minor issues from turning into major repairs.
