Tire — part of a Buick? (7)

I believe the answer is:

exhaust

I believe this clue is a double definition.

'tire' is the first definition.
(exhausting is a kind of tiring)

'part of a buick?' is the second definition.
(part of a Buick car)

(Other definitions for exhaust that I've seen before include "Drain completely" , "Waste gas from engine" , "Car's fume pipe" , "Tire out - waste gases from engine" , "lower part of estate?" .)

I've seen this clue in The Times.

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