Very hot fuel filling container? Good (7)
I believe the answer is:
boiling
'very hot' is the definition.
(I've seen this before)
'fuel filling container? good' is the wordplay.
'fuel' becomes 'oil' (I've seen this before).
'filling' is an insertion indicator.
'container?' becomes 'bin' (bin is a kind of container**).
'good' becomes 'g' (abbreviation).
'oil' placed inside 'bin' is 'boilin'.
'boilin'+'g'='BOILING'
(Other definitions for boiling that I've seen before include "Extremely hot" , "Seething" .)