I have a 2000 3.0 my owners manual says 5w30 synthetic. for engines with a lot of miles i would replace a quart of engine oil with a quart of marvel mystery oil, that stuff is like liquid gold, awesome for fuel systems too

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2000 RANGER XLT 4X4 OFFROAD
3.0L Flex-Fuel EXTENDED CAB, STEPSIDE BED...
32" BFG all terrains, Stainless handles on side of cab, DeeZee chrome bed box, 2" black Bull Bar with lights, Alpine CDE-100 CD Receiver,
Front speakers-Kicker 07DS680 5"x7"/6"x8"s,
Rear speakers 5"x7" Polk Audio MOMO's in removeable boxes for audio outside the truck.