I have replaced the alternator on my 92 Pathfinder SE at least 3 times in the last year. The problem started as a squealing or grinding noise when I first started up the truck. It would sometimes last a couple seconds after the engine started and would go away after engaging the clutch. Then later the noise started appearing when I let the clutch out in first gear. My first thought was the throwout bearing but the noise was only in first gear when I first accelerated. After a couple weeks the noise would come and go as I drove down the road. One day the noise was very bad on the way to work but not on the way home. The only difference was the lights were on in the morning. Sure enough when I turned the lights on, the truck squealed. Turned the lights off, no noise. I also discovered I could get the noise by holding the power window button down after the window was all the way up or down (stalling the motor). Anything that pulled high current caused the squeal. With further investigation I discovered that with the alternator plug pulled or the belt loosened, I could not get the noise. Thus I concluded something is causing the alternator to not want to turn and the squeal is the engine dragging the belt anyway. Two new alternators did this either right after install or after a few days. The last one has lasted 6 months but I haven't driven it that much. The noise is back again so the alternator, although still charging, is destined for failure.

Besides the alternator problem, the fuel and temperature guages do not work 95% of the time (haven't for a couple years) and the truck is running very rough. Tapping on the air flow meter used to smooth the idle out, but now only helps a little. After it's warm, the truck wants to stall every time I come to a stop. I put it in nuetral and rev the engine to keep it from stalling and the squeal occurs; very embarrasing in traffic. I think they're all related and I saw a post somewhere about a voltage regulator on the instrument cluster. Do I need to take the entire dash out to replace it? Any ideas?

Id say if the alternators your using for replacements are rebuilt units from an aftermarket parts house then thats a possibility for early failure due to cheaper parts used when they are rebuilt, your probably better off paying the extra costs in the long run for "New" rather than "rebuilt". Alternator failure can also sometimes be caused by overtightening the drive belt.

I replaced the voltage regulator on the instrument cluster. All
I had to remove was the steering arm top and bottom cover and the panel in front of the instrument panel. The fuel and temperature gauges work now although the fuel says only 3/4's when it's full. The dealer listed 2 different voltage regulators but had only one in stock and it looked the same so I took it. I also discovered a bad connection in the wire to the air flow meter. The truck would barely idle. I happened to touch the wire close to the connector and the idle jumped up and smoothed out. The alternator still makes noise sometimes and I noticed when the grind lasts for a few seconds the voltmeter registers only a little over 12 volts. The belt definitly is not too tight right now and may actually be a little on the loose side. I will try tightening a little. The next alternator will definitely be one from the dealer.

Hello . please advise, my problem seems to be the same...or is it? it started about 2 weeks ago. it seems to make a grinding type of noise when I accelerate , it won't do it all the time but mainly noticeable with windows open and driving between 5 to 55 mph lasts a couple of seconds and goes away... gggrrr and goes away sometimes won't happen for 20-30 minutes i thought it was the fan hitting the cowl since it seems to come from the front ?? please advise ?

I should have remembered to post earlier but a few months back I discovered the problem was not with the alternator but with the belt. Before replacing the alternator with an expensive factory replacement I decided to investigate the noise once more. I noticed that the grinding noise was not as bad when I sprayed with belt dressing so I replaced the belt with one from NAPA. The grinding noise disappeared but the belt squealed like crazy. Tightening didn’t help and I noticed the v-belt did not fit all the way down into the pulley but was riding about 1/8th inch above the groove, the belt pitch was different. I replaced that belt with one from the Nissan dealer; noise is gone now. The dealer belt fits the pulley like it’s supposed to, sitting almost flush with the pulley sides. I then checked the old belt and realized it had worn enough to slip too far down into the groove of the pulley. The belt must have been getting pinched, grabbing onto the pulley, and ratcheting the alternator to death. The grinding noise must have been due to the side pull on the shaft being strong enough to cause the rotor to strike the stator.