A simple but regular oil change is probably the easiest way to keep your
engine running smoothly and enhance its longevity. Your vehicle?s motor
oil can be designated as full-synthetic, synthetic blend, high-mileage,
or conventional by the manufacturer. However, depending on the mileage
of your car and the season of the year, the type of oil and the
viscosity to be used may vary.
This is the oil used in bulk at dealerships and is the cheapest at the auto store, too. Most adhere to API and SAE standards but offer little in the way of additive packages. This is good oil for owners that are religious about frequent oil changes and have low-mile (but well broken-in) engines.
Premium Conventional Oil:
This is the standard new-car oil. Most leading brands have one for SL, or highest level, service. Most are available in the common viscosities. Car manufacturers usually specify 5W-20 or 5W-30 oil, though some require 10W-30. These three ratings cover just about every light-duty vehicle on the road, though this is changing as engines become more precise and fussy about specific types oil.
These oils are made for high-tech engines. If these oils pass stringent special tests (indicated by their labeling), it means they have superior, longer-lasting performance in all the critical areas, from viscosity index to protection against engine deposits. They flow better at low temperatures and maintain peak lubrication at high temperatures. While excellent oil, synthetics are about three times as expensive as conventional oil and not always necessary for most engines. Use the owner's manual as a guide. If it doesn't call for synthetic oil, using it will only be an additional expense that may not add anything to the engine's performance or life.
This is essentially premium conventional oil hit with a dose of synthetic. They're formulated to offer better protection during heavier engine loads and the associated higher engine temperatures. These oils are popular with pick-up and SUV drivers because they do offer better protection, but usually cost only a fraction more than premium conventional oils.
More than 60 percent of vehicles on the road have more than 75,000 miles (120,701 kilometers) on the odometer. Playing to this growing market, oil refiners and labs developed high-mileage oils. Seal conditioners are added to the oil (the oil can be synthetic or conventional) to expand and increase the flexibility of internal engine seals. The conditioners are very precise and can benefit some engines while not affecting others.