Hello everyone, my truck recently started making a terrible grinding noise that speeds up and slows down along with engine speed. I had the truck parked with no accessories running at the time I took this video. Anyone have any kind of idea what this noise is? The engine is a 4.0 ohv.

 

No video

 

Looks like the video didn't upload, it might be too large of a file. I'm gonna get another video later when the truck is cold because the noise is more noticeable when cold. I will upload tomorrow hopefully.

 

Welcome to the forum

2000 4.0l 4x4, should include this with question

Also manual or automatic?

First when engine is cold remove fan belt from crank pulley and start the engine
See if the noise is gone
If so its a bad pulley bearing, shut off engine and spin each pulley by hand

Power steering pulley can not be turned by hand, but if all the other pulleys are quiet then power steering pump is the culprit

You can only run the COLD engine without a water pump for 90 seconds, 1.5 minutes, then shut it off

If you still hear the noise then it should be easier to locate the sound with no Fan noise in engine bay, it will be very quiet
You can repeat this test as much as you like but engine needs to be COLD again


What does starter motor sound like when starting the engine?
Normal or just a little different
Starter gear can come loose a bit and rub ring gear after startup, makes a racket

 

Thank you for your reply, it's a 2000 4.0 liter 4x4 automatic. The starter sounds perfectly normal. I did notice the idler pulley was quite wobbly while the truck was idling. I think I will replace the idler pulley since it looks like it's gone or going and when I have the belt off I'll try spinning the rest of the pulleys and see if anything sounds off. Again thank you for the reply, you gave me some valuable insight. If this doesn't resolve the issue I will follow up.

 

Start the engine when belt is off, you can spin the pulleys by hand before that, but starting the engine will tell you more and if there is still the noise then it will be easier to locate with quiet, engine running, engine bay

 

Will do! Thank you. Hopefully it is one of the pulleys and not a bearing in the engine.

 

Parts finally came in yesterday. Swapped the idler pulley, tensioner, and belt took about 15 minutes and it's all good now. The other pulleys were all good. The tensioner pulley was completely seized. Thanks for your help RonD!