Replace points in a car engine (6)
I believe the answer is:
piston
'car engine' is the definition.
'piston' can be an answer for 'engine' (thesaurus). I am not certain of the 'car' bit.
'replace points' is the wordplay.
'replace' indicates anagramming the letters (I've seen 'replaced' mean this).
'points' with letters rearranged gives 'PISTON'.
'in a' acts as a link.
Can you help me to learn more?
(Other definitions for piston that I've seen before include "Block sliding in hollow cylinder in machinery etc" , "Brass instrument's valve" , "Trumpet part" , "Points about driving rod" , "Valve that's instrumental" .)