What is the best engine oil viscosity for hot climate?

Under high-temperature climates, It is best to choose engine oils with higher high-temperature viscosity to ensure stable lubrication performance in hot environments. For Malaysia's typical tropical climate, synthetic oils such as 5W-40 or 10W-40 are preferable choices, as they maintain sufficient oil film strength at high temperatures and effectively reduce engine wear. Turbocharged models, which operate at higher temperatures, should prioritize fully synthetic oils like 0W-40 or 5W-40, as their high-temperature-resistant additives can withstand extreme operating conditions. Naturally aspirated engines may consider 5W-30 or 10W-30 viscosity grades, provided they meet API SN or SP standards to ensure oxidation resistance. Notably, Petronas Syntium series' 0W-30 and 5W-30 variants utilize CoolTech technology to enhance oil film strength and dissipate heat, making them particularly suitable for high-temperature applications. For high-mileage vehicles, upgrading to 10W-50 viscosity may help compensate for engine component wear.