Request comes in to get engine part (6)
I believe the answer is:
Here is my best explanation:
'engine part' is the definition.
'request comes in to get' is the wordplay.
'request' becomes 'ask' ('ask' can be a synonym of 'request').
'comes in to' is an insertion indicator.
'ask' placed into 'get' is 'GASKET'.
(Other definitions for gasket that I've seen before include "Seal between metal faces", "sandwich filling", "Sealing sheet in an engine", "Sealing ring", "Seal at a pipe point", "Blow that!", "Packing piece used as seal in metal joint", "Flat sheet used as engine seal", "engineering part" and "Compressible piece of rubber forming a seal".)