wondering why "het" is in there?
It is an expression literally " The clock doesn't do it." for the meaning of "The clock doesn't work."
Does "de klok gaat niet" work as well, or is that not among the expressions this verb can form in Dutch?
Nope, but you could say "de klok werkt niet"
"To go" seems to mean a lot more than just getting from one place to another in most European languages, gotta learn what goes in which language.
Can it also mean the clock doesn't do a special function? Does the clock have an alarm? Nee, de klok doet het niet...
Sorry, de klok heeft geen alarm.
Does "de klok werkt niet" have any difference in meaning to a Dutch person than "de klok doet het niet"?
I personally prefer the first option for its more literal translation.
De klok werkt niet makes much more sense.
Is this an expression?
Why not "De klok is stuk"