According to the official vehicle manual recommendation, the 2010 Buick LaCrosse should use 92 octane gasoline. For the 2010 Buick LaCrosse, besides checking the appropriate gasoline grade in the vehicle manual, you can also find this information on the fuel tank cap, which will be clearly marked. Typically, 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. However, with the application of some new technologies, the gasoline grade cannot be solely determined by the compression ratio. Engines with high compression ratios can also be tuned to use lower octane gasoline because, besides the compression ratio, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally, the higher the gasoline octane number, the higher the octane rating 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 the 2010 Buick LaCrosse occasionally uses the wrong gasoline grade, simply switch back to the correct grade after use. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower octane gasoline, using higher octane gasoline will not cause damage, but the increase in octane rating will alter the fuel's ignition point, leading to delayed combustion in the engine. This means the engine's power output and thermal efficiency will decrease, resulting in a noticeable drop in performance. For vehicles recommended to use higher octane gasoline, using lower octane gasoline can cause engine knocking. Because the octane rating is too low, the reduced ignition point may cause the gasoline to ignite prematurely during the compression stroke. If the fuel ignites before the spark plug fires during the compression stroke, resistance will occur during the upward stroke. This resistance can make the engine run very unevenly. If the knocking is mild, it may only increase noise without significant engine damage. However, if the knocking is severe, it indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, even cylinder scoring.
