I know it's not a third gen, but I share your drivetrain. That has to count for something, right?

I have no idea what this is, but it sounds bad. You can hear it a little at 43 seconds in, then really bad at 1:07. It does it whether cold or hot. It is not a belt. It' seems to be coming from inside engine. It has oil in it. It's overheated 3 or 4 times in the past few days, and this started after one of those times. It's also been making some strange clicking noises that I don't know about.

Listen

Any ideas or advice on how to better identify it are welcome.

 

Guessing... Waterpump?

 

x2... pull your belt off the water pump and start it up. if you still hear it, im guessing rod bearing.

 

Sounds like a washing machine.

 

Might be a long shot but check to make sure all your spark plugs are tight. I've heard larger engines make the same noise and that was the cause.

 

Take off the belt, check the water pump (spin it by hand) and the belt tensioner, tensioner pulley, and idler pulley. If none of those show a problem, put the belt on, run it to warm it up, take the belt off and start it and run it for a bit (careful to watch the temp, as the water pump wont be turning) and see if the sound is there.

 

sounds to me like a wiped out bearing or two.

 

now that i think of it, i remember my smog pump making a similar noise. if you are running one, you might want to check that also, you need to break down where the noise is coming from by removing the accessories from the rotation of the engine.

 

Thanks for all the suggestions!

Just so everyone knows, I took the intake off to check the lifters because the squeal stopped but there was a horrible racket still. I found lots and lots of little goldish-copper colored flakes in the oil valley. Every single on of my hydraulic lifters was stuck and the lifters were full of the gold flakes too. I've been in Iraq for the last 17 months, so I decided to treat my engine to some new components after it gets magnafluxed. It's at the machine shop right now. ETA: 2-3 weeks. Future setup: who knows, but if you see a nasty sounding blue Datsun in the Fort Bragg, NC, area after January, be careful. ;-)