2 team expanded to restrict heat and carbon (6,4)
I believe the answer is:
ground crew
'2 team' is the definition.
'ground crew' can be an answer for 'team' (I have seen 'Team of mechanics' mean 'ground crew' so perhaps 'team' could also mean 'ground crew'). I'm not sure about the '2' bit.
'expanded to restrict heat and carbon' is the wordplay.
'expanded' becomes 'grew' (I've seen this in another clue).
'to restrict' indicates putting letters inside.
'heat' becomes 'round' (I can't justify this - if you can you should believe this answer much more).
'and' means one lot of letters go next to another.
'carbon' becomes 'C' (C is the chemical symbol for carbon).
'round'+'c'='roundc'
'grew' going around 'roundc' is 'GROUND CREW'.
Can you help me to learn more?
(Other definitions for ground crew that I've seen before include "Team of mechanics" , "Maintenance men" .)