Loud is usually because the SL loves to floor the
engine. That time SMB29D did 980, also f-ing loud cos I think SL
lambat liao. 1184D is still loud if the SL floors the
accelerator.
There are some bendies that I have experienced, even if they
don't floor it all the way (not using the kickdown switch), the
radiator still works at maximum power and that roaring sound comes
about.
If the engine roars, I think its high time it should head to the
workshop.
The best ones of Woodlands, Habit or Volgren, can be heard over
the sound of all other buses, from one end of the interchange to
the other. I guess you and other Woodlands folks have regular
dosage of that quite some time back, but not really now...