Campaigns to overhaul used cars (8)
I believe the answer is:
crusades
'campaigns' is the definition.
('crusade' can be a synonym of 'campaign')
'overhaul used cars' is the wordplay.
'used cars' anagrams to 'CRUSADES'.
Though, I am unsure how the anagram is indicated.
'to' is the link.
Can you help me to learn more?
(Other definitions for crusades that I've seen before include "wars" , "Military expeditions by Christians to recapture the Holy Land" .)