Oil Viscosity During Warmer Weather

Should your oil viscosity be changed as we head into warmer months? In central New Mexico, our summer temperatures can reach above 100 degrees. As the temperature rises, the viscosity of liquids decreases rapidly. When those liquids like motor oil are then heated, they flow more easily.

Your engine’s oil needs to be thick enough to seal any tiny gaps in your engine and to properly lubricate the metal-against-metal surfaces. However, the oil also has to be thin enough to move easily and circulate where your engine needs it the most. If it’s too thin, the oil can wear down which affects its cooling efficiency.

Today’s synthetic oils offer a more consistent viscosity over a wider range of temperatures, but they're also significantly more costly, and sometimes are not compatible with certain older engines. Synthetic blends combine both natural (or organic) and synthetic oils, and offer many of the benefits of the pricier full synthetic oils, but without the higher cost.

Premium conventional oils are higher quality natural offerings with elevated levels of protection and are required by some cars today. Overall, your vehicle’s type of oil and viscosity largely depend on the climate where you drive, compatibility with your vehicle, and your budget.

How do you know your vehicle’s oil viscosity? Oil viscosity is measured using two numbers followed by a letter. With 10W-40 as an example, the first number (10) references the oil's thickness at cold temperatures (0º Fahrenheit is the baseline), and the second number (40) signifies the oil's thickness at high temperatures (212º Fahrenheit.) While the first number is more important if it’s winter and you live in New Mexico’s cold, snowy regions, the latter is more important once your car is warmed up and traveling the highways. Warm weather calls for thicker oils since they start at a higher viscosity and don’t become too thin when the engine heats up further. More demanding driving such as towing a trailer should require a heavier weight oil.

The single most important source of information regarding your engine oil's specifications and warm weather needs is your car's owner's manual; read it carefully and maintain your engine’s needs according to its specifications. The Service Department is here to help at Melloy Dodge on Coors in Albuquerque, where we service all makes and models. Our No-Appointment Express Lane can handle oil changes for conventional and synthetic oil. If you have any questions about your vehicle, we’re here to help.