Pulling out on I-10 out of Kerrville Texas and was heading back to Houston in my 88 190d ,made it 40 miles of up and down grades in the hill country when I noticed my oil pressure wasnt pegged.Pulled of the interstate to a service station and opened the hood ,the tappets were not sounding good ,really bad feeling when your so far from home.I looked at the oil stick and it was up to snuff just running off the stick like hot butter.I remembered I had purchased my not regular rotella purchase since they were out and went with this motorcraft diesel brand ,bad choice.After I found a Shell station I was able to change the oil out and make my way back home with no issues.Thanks Shell for saving my motor and about a $400 tow.