I bought an '89 S15 Jimmy with 135,000 miles on it. It began to lose oil pressure at an idle, the check gauges light came on and it would die. I put some Wal-Mart Super Tech oil treatment in it. It never did that again. Needless to say, I continued to use it in that vehicle and others. It also helped a '90 GMC C15 I have at present. Good stuff.