I disagree, when you say tightening your not tightening tapts your just adjesting them to there factory setting., your making people misunderstand, its the oem/factory setting for that specific engine at which it will perform on its rated out put hence runs batter.
losening them is making it less responsive.
i dont want to go into further details...
as far was the heat is concerns, its not generating any extra heat, its the heat at which the cooling system is capable of handling.
its the FILLER GAUGE, which is used to adjust the tapts, which mechanic dont have usually..