HELP! Odd Sounds from B210 A14 85% of the time.

[5280Datsun]

So this started yesterday. I need help to identify it.

 

I'll let the videos demo it. In the videos you can hear a few different sounds, the one of the engine bay you can hear it go away a little (although it seems much higher pitched in the video than in real life)

 

Engine Bay: 

https://youtu.be/wipdkHmwsx4

Engine Bay with Rev:

https://youtu.be/vH4L7dySv1c

Inside cab:  

https://youtu.be/OPnhqTPN5ds

Driving through neighborhood:  

https://youtu.be/Dkoe2AdV0hk

• Roughly 30 days ago I changed the belts, the water pump and thermostat. The belts are not super tight either. Refilled and bled the coolant.
•  
• It will go away sporadically and sometimes it does when it's rev'd up, but not always. Sometime cruising speeds, but will come back.
•  
• Doesn't get noticeably louder with RPM increase.
•  
• It makes this noise during driving, idling, cold or hot, doesn't matter.
•  
• It sometimes goes away with high revs or when I let the clutch out and get the RPMs down low.
•  
• Yesterday the oil was on the low side; although no Oil Pressure dummy light came on and oil was full 2500 miles ago. I checked it when I heard this sound and put in about 1.5-1.75 quarts.
•  
• It starts cold or hot no issues.
•  
• It just passed emissions, flawlessly.

 

Thanks almighty engine Gurus! 

 

I hope its not a spun bearing or some internal damage. Hoping maybe its the air pump or alternator (although no issues charging or starting)

 

If this is in the wrong section, please move...

[datzenmike]

Belt tensioner pulley bearing seizing up, I think. Loosen the belt and slip it off. Start it up. If sound gone it is something turned by the belt.

 

Alternator, tensioner pulley or the air pump. Spin by hand... the rough one's the culprit.

[5280Datsun]

I hope before you die science is able to download your brain into a "HAL" type system that will automatically reply to stuff. LOL...

 

Thank you. That's what I was hoping, but it gets dark before I get home. Will diagnose further this weekend.

[Ranman72]

sounds like idler pulley bearing 

do what mike said remove belts and start up to see if its gone 

if it is spin each pulley one at a time you should be able to tell which one is bad 

you can also try a squirt gun or cup of water pour it on the pulley/ belt area you think it is most likely from  usually if its belt or bearing it will change tone in some way or noise will disappear for a short period   

[Stoffregen Motorsports]

To quote HAL - It can only be attributed to human error.