

I just have tried... the F3 car skin has some soundfiles which have no sound inside in fact, mostly the *body.wav sounds.
Then I have deleted the soundless *body.wav files copied the files which actually contain sound (all the files *_exhaust.wav are good) to *body.wav.
And I can hear sound again in Stadium!

I have tried with a different car, same there: body sounds in the ZIP are "empty", after copying the sound is back

Edit:
F3 car with "not working sounds": http://www.maniapark.com/ressource.php?id=1366
F3 car with "fixed sounds": https://www.dropbox.com/s/cnsratz5cb3bto9/F3.zip