Picked up some syntec 5w50 at a k-mart going out of business,couldn't resist it was a 1.50 a quart..Matter of fact i should have bought everything they had, valvoline 10w30 synthetic and some sae 40,but the wife was there and well you know how that goes...Anyway I searched this stuff and see it doesn't get to manay votes of confidence but,would anyone run it in a 89 pontiac grand prix,2.8,120,000 miles??? It never had a steady dose of any one particular oil,dino,semi-synth.,synthetic,high mileage,whatever I had....I usually do 5k oci on this car...Thoughts?????