My dad has a 1984 Chev S10 with the 2.8 V6, I usually am the one who does the oil changes on the truck, I live far away from dad and I know that he hasn't had the oil changed since I did it last summer 4,000 miles ago which of course concerns me, I was considering putting in 15W-40 the next time I visit (maybe pennzoil longlife 15W-40). I remember the owner's manaul said 5W-30, do you think the switch to 15W-40 would be of safe and provide any benefit?
Thanks
Thanks