What are the early warning signs of the timing belt going out on a 1992 Nissan Pathfinder?


There is no warning. Change it every 60,000 miles.

It is true the belt should be replaced at 60,000 mile intervals, but what if you buy a vehicle that let's say has 95,000 miles on it and has had several owners. If you are really cautious you could replace it for piece of mind. But I think in most cases you will find, as long as there are no other issues with the valve train assembly and distributor putting any excess load on the system you might find what I have noticed to be the rule of thumb which is:

When the belt stretches, which it does in time, it will loosen allowing it to slap the inside of the timing belt cover. If this happens prematurely an adjustment is necessary. You will hear a tapping sound that sounds like it is coming from the distributor cap. By taking a stethoscope you can pinpoint it. It is most prevalent with the hood open and sounds dangerously detrimental when revved under no load. From within the vehicle during driving you may only notice it when higher revolutions are made. Considering the price of a new belt compared to the labor, anytime I have had to adjust the tension, unless you know it has been replaced recently, and shows no apparent or unusual wear, I will replace it along with any of the idler bearings that I have any doubt about.