Can I use Auto-Rx with Shell Helix Ultra 5w-40? I recall reading somewhere that Auto-Rx works with Schaeffer Supreme, even though the latter contains some synthetic content, which is a No-no with Auto-Rx.
Incidentally, the Auto-Rx treatment is destined for the fiancee's 2002 Toyota Celica, which has not had an oil service for 16,000 miles. Like many women I know, she does not even know what an oil service or oil change is.
Incidentally, the Auto-Rx treatment is destined for the fiancee's 2002 Toyota Celica, which has not had an oil service for 16,000 miles. Like many women I know, she does not even know what an oil service or oil change is.