2009 Jeep Liberty Owner's Manual - Page 416

414 MAINTAINING YOUR VEHICLE dipstick. Adding 1 quart (0.9 L) of oil when the reading is at the bottom of the SAFE zone will result in a reading at the top of the safe zone on these engines. CAUTION! Overfilling or underfilling the crankcase will cause aeration or loss of oil pressure. This could damage your engine. Change Engine Oil The oil change indicator system will remind you that it is time to take your vehicle in for scheduled maintenance. Refer to the "Maintenance Schedule" in Section 8 of this manual for information on this system. NOTE: Under no circumstances should oil change intervals exceed 6,000 miles (10 000 km) or six months, whichever occurs first. Engine Oil Selection For best performance and maximum protection under all types of operating conditions, the manufacturer recommends engine oils that are API Certified and meet the requirements of Chrysler Material Standard MS-6395. American Petroleum Institute (API) Engine Oil Identification Symbol This symbol means that the oil has been certified by the American Petroleum Institute (API). The manufacturer only recommends API Certified engine oils.