aaron, the 83 is a replacement for a 79 that i lost. that was stinky. seriously, the temperature here yesterday was 40 -45 degrees f. driven mb diesels now about 50k miles. never saw this pulsating before. as new purchase, i changed oil and filter. used the usual 15w -40 dino rotella. (fuel filters and valve adjust for completeness of proceedures done by me).