Turning point of empty car is doubled (6)
I believe the answer is:
crisis
'turning point' is the definition.
(I've seen this in another clue)
'empty car is doubled' is the wordplay.
'empty' says to hollow out the word (remove centre letters).
'doubled' says to double the letters.
'car' with its centre removed is 'cr'.
'is' duplicated is 'isis'.
'cr'+'isis'='CRISIS'
'of' acts as a link.
(Other definitions for crisis that I've seen before include "Difficult moment" , "Decisive moment, turning point" , "Time of decision or acute danger" , "mess" , "Moment of danger" .)