quote:LS1 based motors (4800, 5300, LS1, LS6, 6000) like thick oil. Many here use a blend of Mobil 1 15W-50 and 10W30. He will likely have a slight mpg lose 1-2% peak bhp from the pumping and windage losses. My suggestion? Run it 7500 mi or until lows get below 40F (4.4C). Gene
Originally posted by mgm13: My brother just put 6qts of Mobil 1 15w50 in his 2000 GM 5.3. 70,000 miles no noise no usage no problems on Mobil1 10w30. Deep S Texas 100+. Question is what will this do to his engine and whats the best fix short of dumping $24 worth of new oil? Help pls.