20,000 miles Mobil 1™ Extended Performance High Mileage is an advanced full synthetic motor oil that protects for 20,000 miles between oil changes2 and is formulated to prevent leaks and damaging deposits.

With Mobil 1 Extended Performance synthetic motor oil, you get proven protection up to 20,000 miles, guaranteed. It's an advanced full synthetic formulation and offers outstanding all‐around protection that outperforms our synthetic blends and many of our regular full synthetic motor oils.

Mobil 1 Extended Performance synthetic oil is recommended for oil change intervals up to 20,000 miles or one year, whichever occurs first.

Yes. Mobil 1 is fully compatible with conventional motor oils, semi‐synthetic motor oils and other synthetic motor oils, should it be necessary to mix them. But the superior performance of Mobil 1 will be reduced by diluting it.

Synthetic Oil Change Interval Most synthetic oils are rated to last between 10,000 to 15,000 miles, or six months to a year. Manufacturer recommended ratings are typically applied to "normal driving," and don't reflect severe driving conditions that may require more frequent oil changes.

Overfilling can damage the engine. Most auto manufacturers recommend oil changes once each year or 20,000km on petrol engines. Diesel engines and turbo charged petrol engines should be changed every 6 months or 10,000 km. Changing the oil once a year (20,000 km) is OK for vehicles driven in ideal circumstances.

OIL LIFE ISSUES Neglected oil change intervals can ruin the best engine oils. As engine oil accumulates miles, it becomes contaminated with carbon, water and various acids, all of which are a by-product of internal combustion and which will form a film of black, gooey sludge on the interior parts of the engine.

“While synthetic generally holds up better and can serve for more miles, it is equally important to not extend oil changes beyond the time interval recommended by the manufacturer - typically six months or a year if it is a motor that is not driven many miles or on many short trips.”

Oil companies and automakers would like you to change your oil at 15,000 or 20,000 miles, especially with high-quality synthetic oils. Still, there are real dangers in adopting such long oil change intervals, especially if your car wasn't made for it.

Yes. There is no danger mixing synthetic and conventional motor oil. However, conventional oil will detract from the superior performance of synthetic oil and reduce its benefits.

A: Yes. This is a practical method to improve oil pressure in an older, high-mileage engine. The slightly thicker oil film from the heavier base weight oil - 10W - can help protect worn engine bearings as well.

“While synthetic generally holds up better and can serve for more miles, it is equally important to not extend oil changes beyond the time interval recommended by the manufacturer - typically six months or a year if it is a motor that is not driven many miles or on many short trips.”