Nissan: 95 Sentra Power Steering Problem

I've got a 95 Sentra with a minor power steering problem.
When I first start it up, the power steering is very stiff.
I can hear the belt slip when I turn the wheel. Within about
30 seconds, though, the power steering starts working. So,
either it doesn't work when the engine's cold or it doesn't
work until it's been used for a few seconds. As far as I
know, the belt isn't loose.

Anyone care to hazard a guess at the most likely cause?

Steve DeGroof wrote:
 

Loose belt. These newer multiribbed belts have to be tensioned much tigher
than V belts to not slip, especially when cold.
--

Steve

http://www.atlantaracing.com