A4 B8 - Engine Scraping / grinding noise

[Paul Allen]

Hi folks,
how's things?
I have a very loud Scraping / Grinding sound on front of my engine. The noise is external, as apposed to inside the block. It could be coming from either the timing area, the serpent belt adjuster, one of the pumps or the Alternator, I can't work out which.
The first 3 days it made the noise I crapped myself, thinking the engine was about to explode, or something was going to fall off. By the time I opened the bonnet the noise had gone. The noise was/is like twisting a shuvel inside a metal bucket, but at a constant faster speed, maybe twice a second at tickover/idle, and scraping more on one side of the bucket than the other. After the choke closed the noise went away within a few seconds and the car drove without issue.
On the 4th and 5th days the noise didn't go away, but again became quieter (more quiet) as the choke closed & the revs dropped, which I would think to be logical; it is still quite loud, as opposed to very loud. The noise does increase with revs, as I assume would be expected.
The engine starts & runs ok, but does appear to run a little laboured, but only a little...
I have my suspicions, but thought I'd throw it out there to see if anyone agrees. Any suggestions or advice would be appreciated and gratefully received.
Thanks,
Paul.

Car: Audi A4 B8 2.0 TFSI Quattro S-Line 2009.

 

[Paul Allen]

Update:

This turned out to be a destroyed balance shaft chain and crank shaft cog teeth.

 

[quattrogone]

Crikey! You don't seem to have had much luck with this
How many miles has your car done?

 

[Paul Allen]

No, it's been a bit of a nightmare & I've hardly driven it for the last year, but to be honest, it's mainly my fault for not servicing & maintaining properly. I've pretty much replaced everything you can replace, water pump, N80 Valve, Cambridge/solenoid (mesh blew because of broken PCV), Chains/Tensioner, Crank Cogs, Belt/Tensioner, PCV Valve, all Bolts/Clips on front of car because I've taken it apart so often... Lol. It's annoying too because all the specialists either wouldn't touch it or just didn't know, so I did all the work myself...!

I've had other issues since & still have another. I was getting a low oil pressure warning, but it turns out it may have been related to the reverse camera I'd installed; I was powering it off the reverse light but since I installed its own relay feed the low oil pressure warning has gone (hopefully). I also need to replace the camshafts because the Cambridge mesh damaged the ends & I keep having to replace the bridge when the grooves transfer & the oil doesn't flow properly...

Anyway, it kept me busy during lockdown... LOL

P.S. It's done 105k miles...

Edit: the low oil pressure warning only occured when I turned the heater on...!

 

[quattrogone]

Well kudos to you for learning mechanics if you don't already do it for a day job!
Good luck from here on with it hopefully you can see some light at the end of the tunnel

 

[Paul Allen]

Cheers Quattro gone...

I'm not a mechanic no, but sometimes needs must. :0)

Fingers crossed...!