What type of engine oil is suitable for the Buick GL8?
3 Answers
According to the manufacturer's recommendation, the Buick GL8 uses 5W30 engine oil. The type of oil a vehicle should use should be based on the manufacturer's recommendation. The recommended oil specification can be found in the vehicle's user manual (maintenance manual), which provides detailed explanations. As long as it is 5W30 oil, any brand of oil can be used, provided that the oil is genuine. Below is an introduction to automotive engine oil: Composition: Engine oil consists of two parts: base oil and additives. The base oil is the main component of lubricating oil, determining its basic properties. Additives can compensate for and improve the shortcomings of the base oil's performance, endowing it with certain new properties, making them an important part of lubricating oil. Selection of lubricating oil brands: If you prioritize the longevity of the oil, you can choose Mobil oil; if you care about the oil's cleaning ability for the engine, Shell oil is recommended; if you need lubricating oil with strong oil film toughness, you can opt for Castrol. When replacing the engine oil, it is necessary to simultaneously replace the oil filter. The oil filter is used to filter out impurities, metal shavings, sludge, and other contaminants from the oil. Only filtered oil can remain clean, extending the service life of both the oil and the engine. If the oil filter is not replaced when changing the oil, the contaminants retained in the filter paper will contaminate the new oil, causing it to turn black quickly. Additionally, if the oil filter is not replaced for a long time, its filtering effectiveness will significantly decrease, mostly failing to achieve the desired filtering effect. Prolonged driving under such conditions will rapidly wear out the engine's internal components, and in severe cases, it may lead to oil burning. It is recommended to replace the filter along with the oil. The viscosity of engine oil changes with temperature, so special attention should be paid to its performance under both low and high temperatures. For example, in 5W-30, the first number indicates low-temperature fluidity, with 5W representing the ability to withstand temperatures as low as -30°C. The smaller this number, the better the low-temperature fluidity, ensuring smoother cold starts for the car. The latter number represents the oil's kinematic viscosity at 100°C, with higher values indicating better ability to maintain viscosity at high temperatures, which can also be understood as better lubrication performance under high-temperature conditions. When selecting engine oil, the following considerations should be kept in mind: Choose oil based on the engine's requirements. It is unnecessary to use overly advanced oil in engines with lower requirements, nor should lower-grade oil be used in engines with higher requirements. Multigrade oil should be preferred whenever possible. Due to its efficiency, long service life, and high performance, multigrade oil provides better protection for the engine. Based on the characteristics of multigrade oil, it may appear darker and have lower oil pressure compared to conventional oil during use, both of which are normal.
After driving the GL8 for so long, I've found that engine oil depends on the specific model and year. The older 3.0L naturally aspirated version runs smoothly on 5W-30 full synthetic—my 10-year-old car has always had quiet engine noise with this grade. The newer 2.0T turbocharged model, however, must use 0W-20 with dexos1 certification. The 4S technician said all China-6 vehicles must stick to this green label, or the particulate filter may clog. Last service, they almost talked me into using 5W-40—luckily, I checked the manual; thicker oil just increases fuel consumption. Always bring the owner’s manual for service—oil capacity varies by displacement too. The 28T model needs 5.7 liters; overfilling makes the engine feel sluggish.
As fleet administrators, we uniformly use Castrol Edge 5W-30 with GM certification for our dozen GL8 vehicles. During the break-in period of new cars, we opt for a thinner 0W-20 oil, and switch to 30 viscosity after exceeding 50,000 kilometers. It's crucial to check for GF-6 or SP standards on the oil container—avoid lower-grade SL oils, especially since all our vehicles are now China-6 compliant. Before long summer trips, I always have our mechanics inspect the oil condition, particularly for turbocharged engines prone to oil degradation. I recall an instance when a vehicle's engine light came on due to a repair shop mistakenly using mineral oil, leading to carbon buildup. Although full synthetic oil is more expensive, its 10,000-kilometer change interval proves more cost-effective.
