Whether using thicker engine oil can reduce engine noise requires comprehensive consideration of multiple factors, as either excessively high or low oil viscosity may backfire. From a technical perspective, excessively high oil viscosity increases the rotational resistance of the crankshaft, leading to power loss and higher fuel consumption. Additionally, excess oil may enter the combustion chamber, forming carbon deposits that increase piston movement resistance and ultimately exacerbate noise. Conversely, excessively low viscosity makes it difficult to form an effective oil film at high temperatures, resulting in insufficient lubrication and component wear. Therefore, selecting an oil within the viscosity range recommended by the vehicle manufacturer (such as 5W30 or 0W40) is more critical. For instance, Shell Helix Ultra 5W30 significantly inhibits carbon deposits and sludge with its PowerClean dispersion technology, delivering outstanding noise reduction below 1500 rpm. Meanwhile, German GT Magic Red 0W40 achieves noise reduction under high-temperature conditions through PAO base oil and liquid molybdenum additives. For high-mileage vehicles, slightly increasing viscosity (e.g., to 5W40) can compensate for component wear gaps, but blindly using ultra-high-viscosity oil should be avoided. It is advisable to prioritize noise-reducing products like Shell and GT Magic Red, regularly replace the engine oil and filter to maintain optimal performance, and avoid mixing different oil brands to prevent adverse chemical reactions.
