15W-40 in 1984 S10 V6

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Oct 11, 2002
Pullman WA
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
Well, if its using oil, a 15W-40 would be O.K. But if its not using any a 10W-30 either GTX, or Chevron Supreme would be a good choice. These oils have held up well. And no- the 15W-40 really won't hurt anything. It probably would not be very suitable for winter though.
Might check the Owners Manual to be sure. I had a 1986 S-10 with the 2.8L V-6 motor and at that time GM allowed 15W40 in that motor so I suspect you could use 15W40 in a 1984 S-10 motor. I used 15W40 (Rotella)in the Summer months after it got a few miles. However, if it is not using oil, 5W30 or 10W30 would be fine.
He lives in the tri-cities (WA) they get pretty mild winters, dosen't get much below freezing. I think I'll wait for a good 15W-40 to go on sale and pick up some. Thanks.
Would you have that 15W-40 out before winter? It's OK for those summers, but probably too thick for winter in the Palouse. There are some diesel/gasoline 10W-30 oils (API CH-4 and SL), but they're hard to find. Ken [ May 12, 2003, 12:14 PM: Message edited by: Ken2 ]
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