[R129 SL] Underhood smoke from my '97 SL500...

[mid-co]

1st....you ,  or your mechanic must determine
why the car needed coolant in the 1st place.
.Was  / is the car running hot ??
What's the condition / age of the coolant
hoses ?...there are many possibilities
here.

Yes...you might be endangering your
engine.

If you're not comfortable with your
own trouble shooting skills  (or just
don't have the time)  , I'd have the
car flatbeded to a trusted svc center .

Bruce in Nashville.