In Dublin see diesel oil producer? (7)
I believe the answer is:
linseed
'oil producer?' is the definition.
(linseed oil)
'in dublin see diesel' is the wordplay.
'in' indicates a hidden word.
'LINSEED' is hidden within 'dublin see diesel'.
(Other definitions for linseed that I've seen before include "Source of plant oil" , "Enisled (anag.)" , "Type of oil" , "Part of flax used as oil" , "Oil produced from flax" .)