Barrybed

I was driving my "93 Pathfinder a couple of days ago and a terribly loud, metalic grating noise came from the engine compartment. It went away as I accelerated and came back as I drove at a consistant speed. I was able to make it home. I was a little low on oil so I added a quart and heard no noise for a couple of days. Then one morning I started it up and there it was again. The next day I drove it and it was gone. This does not sound like power steering, I have heard that. This is like someone scraping the inside of a metal drum. Has anyone ever experienced this..Thanks in advance..

Animal

Loud noises internal to the engine usually do not disappear with excelleration, normally this makes it worse, nor do they normally come and go. So lets assume, for now, that the problem is exteral to the engine. Nearly all moving parts are around the front of the engine. Something loose and hitting the fan can make a lot of racket. Check to make certain the fan shroud is secure, etc. The idler (tension) pully for the A/C can also make a nasty noise, but usually it's more of a screech; the alternator can as well. Check your engine mounts by starting the engine opening the hood and give the throttle a quick "punch" while watching the engine torque. The side to side movement of the intake should only be slight, perhaps about an inch. If it is an automatic, bad engine mounts will usually be apparent by watching the engine while going from park to reverse to drive. If you do this, get someone you trust to hold their foot on the brake and shift while you watch.