Synthetic vs. Conventional Motor Oil—How? When? Why?

Synthetic vs. Conventional Motor Oil—How? When? Why?
Synthetic vs. Conventional Motor Oil—How? When? Why?

I feel sorry for the average consumer or do-it-yourselfer who decides to buy engine oil at an auto parts store or big-box retailer. There are all kinds of claims for all types of vehicles — high-performance, high-revving engines; high-mileage older cars; heavy-duty pickups and SUVs; and so on. What’s your ordinary driver supposed to do? The owner’s manual is the place to start. But how do you know which oil to pick, and whether to go with conventional or synthetic?

The standard new-car oil is typically a premium conventional (mineral) oil. Service-level SM is the current designation, available in a variety of viscosity grades. Most car manufacturers suggest 5W-20 or 5W-30. Conventional oil works very well. With regular changes any engine can achieve 200,000 miles.

Many manufacturers are now recommending fully synthetic oil in their high-tech engines. Corvettes and most Mercedes-Benz cars come with it as a factory fill. Synthetic oils pass strict tests and offer longer-lasting performance when it comes to their viscosity index and protection against deposits. Synthetics also flow better at colder temperatures and maintain excellent lubricity at higher temps. Plus they don’t evaporate as easily, giving them better longevity. But there’s a catch:  Along with being more expensive, not every engine needs them.

Synthetic blends offer better protection for heavier loads and higher temperatures. They’re a good choice for motorists who put heavy loads on their engine, such as towing or off-road use. Semi-synthetics offer many of the same benefits of full synthetics, but at a fraction of the cost.

Check with Your Tech—at Quality Automotive.

St. Louis’ Choice for the Automotive Voice!