All I can say is I didn’t think my diesel could run any better/ cleaner than it did, I was skeptical to say the least but after the terraclean diesel procedure undertaken at Atherton car safety centre ltd the word I would use is refreshed. The car feels as i would imagine it felt when it was new 10 years ago, smoother, more responsive and I’m getting 3 to 4 mpg more than before. Highly recommended.