Pennzoil 550038271 20W-50 Motor (SN) 5qt jug Cleans out up to 40 percent of engine sludge in the 1st oil change; Continues to clean in the second oil change Helps prevent sludge and other damaging deposits 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 Enhanced emission system protection compared to GF-4 and earlier service categories