Just bought it: 2002 Chevy 1/2 ton van 5.7L engine 210K miles on it 5w-30 Pennzoil dino in it now According to original owner, has had either 5w-30 synthetic or dino in it 3K changes with the dino, 7.5K changes on the synthetic. I haven't looked at the inside of the engine. Current fill of dino has 1K on it, looks in good condition, I had to add 1/2 qt. Original owner says it uses about a qt of oil per oil change. I plan on driving it once a week or so, highway miles, going easy on it. Van has resided in south Texas it's whole life. I have all the receipts on everything done on it since new, well maintained. Seems to have a small leak, but seems like it's the tranny. What oil do you guys recommend I use?