Mobil 1™ Annual Protection motor oils are our ultimate full synthetic motor oils, providing proven protection for one full year or up to 20,000 miles between oil changes, whichever comes first*, while keeping your engine running like new.

Mobil 1 uses all polyalphaolefins (PAO) as basestocks. Some less expensive brands use polyisobutylene as a thickener instead of 100 cSt PAO. Mobil 1 uses alkylated naphthalenes as the cosolvent. Some less expensive brands use diesters.

As engine oil ages, it breaks down and becomes less effective at doing its job. Most manufacturers recommend getting the oil changed at least once per year, no matter how few miles you've spent on the road.

Auto manufacturers agree. Testing under the current industry performance standard from the International Lubricants Standardization and Approval Committee (ILSAC) shows that Mobil 1™ outperforms not only conventional motor oils, but other full synthetics as well. In fact, it performs far better than industry standards.

Because Mobil 1 works much faster, the engine reaches peak operating efficiency much sooner. Mobil 1's robust antioxidant system resists oxidation and oil thickening better than conventional oils, resulting in lower friction and better fuel economy.

Once opened, motor oil will be good for 2-5 years. if unused during that timeframe, it will start to break down and lose its effectiveness. How Long Can You Go Without an Oil Change? Most motor oils will last for about 5,000 miles before they need to be replaced.

Regardless of how often you get your oil changed, you should check the oil level monthly and top it up as needed. If you don't drive much, most automakers recommend changing the oil annually, even if the maintenance reminder hasn't appeared yet.

Not only does AMSOIL exceed industry standards and outperform competing brands, it fights viscosity breakdown 46% better than Mobil 1. It's built to stand up to the devastating effects of high-horsepower, modern engines and provide maximum protection.

My engine oil is less than 3,000 miles but more than a year. Do I need to change oil already? I asked a PhD petroleum engineer friend the same question. He said that the oil is stable for more than a year but the additives break down regardless of whether the car is driven.

If the oil is unused, and unopened, there is nothing wrong with using it. ExxonMobil recommends a five-year maximum shelf life for engine oils, including Mobil 1™ synthetic motor oil. Opened oil can vary in shelf life due to extreme temperature, humidity and other conditions like dusty environments.

At some point, the oil is no longer protecting the sliding surfaces within the engine as well as it should. Engine wear accelerates after the oil breaks down or is highly contaminated. And finally, almost no automaker recommends that oil should be left in the crankcase for more than one year - no matter the mileage.

Go long enough without an oil change, and it could eventually cost you your car. Once motor oil becomes sludge, it no longer draws heat from the engine. The engine might overheat and either blow a gasket or seize up. The milky white exhaust of a blown head gasket will force you directly to the side of the road.