Should the Regal use 5w30 or 5w40 engine oil?

[DelAriel]

The Regal uses 5w40 engine oil. The functions of engine oil are: 1. To reduce wear between the piston and cylinder, as well as between the main shaft and bearing bush, providing lubrication; 2. To assist in cooling the engine internally; 3. To clean carbon deposits, sludge, and metal particle impurities from engine components; 4. To minimize gas leakage and prevent external contaminants from entering; 5. To cushion and absorb shocks from the piston, piston chips, connecting rod, and crankshaft bearings. Taking the 2020 Regal as an example, it belongs to the mid-size car category with body dimensions of: length 4904mm, width 1863mm, height 1461mm, a wheelbase of 2829mm, and a trunk capacity of 441 liters.

[SanAngela]

My Buick Regal has been running for five or six years, and I've always used 5W30 oil—it feels just right. The dealership recommended it when the car was new, saying it offers good fluidity during cold starts and protects the engine. Even during long summer drives or in traffic jams when the engine runs hotter, 5W30 provides effective lubrication and prevents wear. A friend of mine tried 5W40 in northern winters but found it harder to start because it's thicker, and it even increased fuel consumption. The maintenance manual usually specifies 5W30 as the standard choice, with an oil change interval of every 5,000 kilometers—don’t skimp on this small expense, as it genuinely extends engine life. Whether driving in the city or on the highway, it runs quietly, hassle-free, and cost-effectively. If your car is relatively new, don’t hesitate—just stick with 5W30.

[DiAdriel]

I've handled numerous Buick Regal maintenance cases, and when owners ask me about oil selection, I always emphasize considering engine condition and driving environment. For regular city driving, 5W30 is the factory-recommended best match, with viscosity performing well-balanced from -30°C to high temperatures, protecting bearings and pistons. If your car has over 80,000 kilometers or frequently carries heavy loads on highways, 5W40 might be more suitable - its slightly higher viscosity can fill piston gaps to reduce wear. The 'W' in oil stands for winter fluidity - the lower the number, the smoother cold starts. Regardless of type, changing oil every six months is crucial - don't wait until engine knocking sounds appear. Simple method: check your owner's manual or have a professional shop scan to confirm the exact specification - safety first.

[Drew]

I've been using 5W30 in my Buick Regal for years—it's economical and practical, providing good fuel efficiency and protection. For new cars, just follow the manual; 5W30 is sufficient unless you frequently drive long distances in extremely hot desert conditions, where 5W40 might be too viscous and increase fuel consumption. In terms of price, 5W30 is usually 10-20% cheaper than other options, with the same oil change interval of every 5,000 kilometers, saving you a significant amount in the long run. Don't skimp on maintenance—replace the oil filter and air filter as needed to keep the engine durable. Check the oil level during hot summer months to avoid shortages, as safe driving starts with maintenance awareness. Choosing the right oil makes car care effortless.