Pennzoil 550035091 Motor Oil Lubricant, 1 Quart It exceeds the demanding requirements of International lubricant Standardization and Approval Committee GF-5 Cleans out up to 40 percent of engine sludge in the 1st oil change. Continues to clean in the 2nd oil change Helps clean up engines by gently lifting sludge deposits off engine surfaces and dissolving them safely into the oil Controls high-temperature oxidation and deposits