I have a slight noise coming from the lower part of my 4.7L V8 on my 02 Ram, its not all that loud from the cab, a slight rattle on idle and hard to notice when revved up. A bit more noticeble when standing by the side of the truck.

Wondering what this may be and if its something to be concerned about.

 

That would concern me. Sounds like metal hitting hard or something...

 

You might want to take off the belt and run it briefly (very briefly) to see if it's anything in the belt path. Could also be a valve issue but you did say it sounded like it's coming from the bottom? Has the truck been run low on oil? Have you recently checked the oil?​​​​​​

 

Yes, sound coming from the bottom, hard to hear when standing in front with hood open and definitely no sounds from under valve covers or even in front around timing chain area.
Truck was over filled with oil when I got it by about 2 quarts. Did an oil change a month back and its filled correctly now but previous owner ran it for a year without changing oil and likely overfilled for much of that time.

 

It sounds like valve train noise...... but, that wouldn't be coming from the bottom of the motor..... doesn't really sound like rod, or main bearing knock to me......

 

Yah I originally thought it was something with the motor, but since it's supposedly under the truck i'm thrown for a loop... Maybe a bolt or something is loose like a mount?

 

It's definitely a rotational noise, as it increases in frequency with engine speed..... It may all well be a rod knock..... it just doesn't sound that way on the video...... As suggested above, when the engine is COLD, take off the serpentine belt, start the motor? Noise still there??

 

Tried to take the serpentine belt off and the tensioner arm seems frozen - bolt on idler pulley tightens when turning clockwise instead of lifting the arm. Triple checked I'm turning the right way and as per the 4.7 guru Martin Built's Youtube channel I am. bolt keeps tightening and worried I will break it off if I continue trying. Funny thing is, when Martin got his new belt on and fired up the engine his rattles like a diesel and someone even commented it sounded like a Cummins!

Will have to figure out how to unstuck the tensioner arm, sprayed it with lots of wd40 to sit overnight anyway. Maybe a jack with wood for slight pressure?

 

WD 40 probably isn't going to help. It is a lubricant, but, not really that effective against corrosion. PB Blaster, or similar works MUCH better.

That said, just putting a chunk of 2x4 against it, and rapping on it, trying to get it to move in EITHER direction will eventually work. Once you get it to break loose, just keep working at it until is moves enough to get the belt off. Then replace it. Maybe a new belt as well.

 

Hopefully you are just using the wrong term here, but it's not the idler pulley you should be trying to pull on, as that's fixed. It's the tensioner pulley which sits to the left of the idler and is the left-most pulley when standing in front of the truck.

If you're using a regular ratcheting wrench, you'll probably need to slide a pipe on it for leverage... or you can use a breaker bar.