What are the effects of adding the wrong 92 gasoline to a GL8?
3 Answers
If a GL8 occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower-grade gasoline, mistakenly using higher-grade gasoline will not cause damage, but the increase in octane rating can alter the fuel's ignition point, leading to delayed combustion in the engine. This results in reduced engine power and thermal efficiency, with the actual experience being poorer performance. For vehicles recommended to use higher-grade gasoline, using lower-grade gasoline can cause engine knocking. Because the octane rating is significantly lower, the reduced ignition point may cause premature ignition during the compression stroke. If the fuel ignites before the spark plug fires, resistance occurs during the upward stroke. This resistance makes the engine run very unstably. If the knocking is imperceptible, it only increases noise without significant engine damage. However, noticeable knocking indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring. According to the official vehicle manual, the GL8 should use 95-octane gasoline. In addition to checking the recommended gasoline grade in the vehicle manual, the GL8's fuel cap also indicates the appropriate grade. Generally, the gasoline grade can also be determined based on the engine's compression ratio. Vehicles with a compression ratio between 8.6-9.9 should use 92-octane gasoline, while those between 10.0-11.5 should use 95-octane gasoline. However, with the use of new technologies, the compression ratio alone cannot determine the gasoline grade, as high compression ratios can be tuned to use lower-grade gasoline. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, higher gasoline grades have higher octane ratings and better anti-knock properties. 92-octane gasoline contains 92% isooctane and 8% n-heptane, while 95-octane gasoline contains 95% isooctane and 5% n-heptane.
One day I drove my GL8 to a self-service gas station and accidentally selected 92-octane fuel. After filling up, I immediately noticed something was off. The engine occasionally made a knocking sound, similar to detonation, and the throttle response felt sluggish with noticeably slower acceleration. I asked a car-savvy friend about it, and he explained that the low octane rating caused abnormal combustion, which could damage pistons or spark plugs over time—costly repairs. He recommended adding an octane booster and driving gently until the tank was nearly empty before switching back to 95-octane. Since then, I always double-check the label to avoid mishaps. For modern turbocharged GL8 models, the impact is even greater, with higher risks during high-load driving—never overlook this small detail.
My car repair experience tells me that using 92-octane gasoline in a GL8 is definitely not acceptable. Low-octane fuel is prone to pre-ignition in high-pressure environments, causing knocking phenomena that damage internal engine components such as valves or bearings. In the short term, you may only notice reduced power and increased fuel consumption, but long-term use can lead to oil leaks or engine failure, which can be costly to repair. I recommend that owners check the malfunction indicator light immediately upon discovery, dilute the fuel in the tank, or replace the gasoline. It's best to develop the habit of checking the fuel pump label carefully to avoid such mistakes and save unnecessary expenses.
