Ancient Aussie car doesn't start (5)

I believe the answer is:

olden

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'ancient' is the definition.
(as in the olden days)

I cannot understand how the rest of the clue works.

(Other definitions for olden that I've seen before include "Bygone" , "(Of days) in the long distant past!" , "Of a former age" , "as in time gone by" , "of ancient history?" .)

I've seen this clue in the Sydney Morning Herald.

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