Can the Buick GL8 use 5W40 engine oil?

[SanBrielle]

The Buick GL8 can use 5W40 engine oil, but the owner's manual specifies 5W30. Below is a detailed introduction: 1. Introduction 1: Compared to 5W30 engine oil, 5W40 has better low-temperature fluidity and is suitable for environments above -35°C. It also offers superior high-temperature protection and sealing performance. However, due to its higher viscosity, it increases engine running resistance and fuel consumption. 2. Introduction 2: Naturally aspirated engines have lower requirements for engine oil and can use mineral or semi-synthetic oil. If the budget allows, fully synthetic oil can be used. Compared to naturally aspirated engines, turbocharged engines have a more compact structure and operate under more complex conditions, requiring higher-quality engine oil with better fluidity, preferably fully synthetic oil.