What grade of gasoline should the Highlander use?

[Queiroz]

The Highlander officially requires 97 octane gasoline and should not use any grade below 97. Here is some relevant information about gasoline grades: 1. The commonly referred to grades such as 90, 93, and 97 represent the octane rating, which indicates the gasoline's anti-knock properties compared to standard gasoline. Using a lower octane gasoline in a high-compression engine can cause knocking, accelerate component wear, and lead to mechanical issues. 2. Vehicle owners should choose the appropriate gasoline grade based on their engine's compression ratio. The recommended gasoline grade is usually specified in the vehicle's manual. For example, mid-range cars with a compression ratio between 8.5-9.5 should use 93 octane gasoline, while cars with a compression ratio above 9.5 should use 97 octane gasoline. Attempting to save costs by using a lower octane gasoline will ultimately be more detrimental than beneficial.

[LauraFitz]

My old Highlander has been running for over six years, and the manual clearly states that 92 octane is sufficient. The gas station attendant always tries to persuade me to use 95 octane, claiming better performance, but after trying it a few times, I hardly noticed any difference—the throttle response felt the same. Later, I asked a seasoned mechanic at the dealership, and he explained that naturally aspirated engines aren’t that delicate. Higher-octane fuel might even lead to incomplete combustion and more carbon buildup. Now I stick to 92 octane, saving 30-40 yuan per tank, which adds up to enough for my kid’s toys. If you drive a hybrid or a newer model, always check the fuel cap—some require 95 octane, and that’s not something to overlook.

[SanEmerson]

Twenty years of car repair experience tells you that fueling a Highlander depends on the engine. For the older 2.7L/3.5L naturally aspirated engines, 92-octane gasoline is just right. A couple of years ago, I worked on a car that had been using 95-octane fuel, and upon opening the engine, the valve carbon buildup was twice as thick as in a regular car—the owner wasted money for nothing. Special attention is needed for the new hybrid models. The A25 engine in these has a high compression ratio, and the manufacturer mandates 95-octane fuel; otherwise, the check engine light will come on without hesitation. When owners worry about fuel consumption, I always say the most practical thing is to check the fuel cap label for the recommended octane rating—just follow what the manufacturer specifies, and you can't go wrong.

[DiCarlos]

From a mechanical principle perspective, the recommended fuel grade for the Highlander depends on the compression ratio. For naturally aspirated engines before the third generation with a compression ratio of 10-11:1, 92 octane fuel provides more than sufficient anti-knock performance. However, the current hybrid model's A25 engine has a compression ratio increased to 14:1, requiring 95 octane to prevent knocking. In a real-world test I conducted, using 95 octane in an older model actually increased fuel consumption by 0.8L/100km because higher-octane fuel burns slower in low-compression engines. It's also worth noting that some private gas stations' 92 octane fuel may not meet the actual octane rating - in such cases, mixing in some 95 octane is better than using purely substandard fuel. Regularly using fuel system cleaner to clean the injectors does prove effective.

[EmilianoLynn]

When refueling, just focus on three key points: First, check the owner's manual to confirm the required octane rating - pre-2018 Highlanders can generally use 92 octane without issues. Second, for newer hybrid models, always check the fuel filler door - if it specifies 95 octane, never compromise. Finally, when encountering aggressive driving or fully loaded hill climbs, it's fine to temporarily use a tank of 95 octane to prevent knocking. During my Highlander trip on the Sichuan-Tibet route, I found that using 95 octane in high-altitude areas indeed provides better throttle response. However, for daily commuting, it's unnecessary - forcing 95 octane into a vehicle manufacturer-rated for 92 not only wastes money but may also cause premature failure of the catalytic converter.