A4 B8 - Loud Engine Scraping / Grinding noise

[Vorlockfoss]

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.

[Magnet]

Hello Paul, 

My starting point would be to remove the auxiliary belt to confirm noise disappears. 

Kind regards,

Gareth. 

[Vorlockfoss]

Hi Gareth,

Thanks for the above advice. It's obvious now you've said it... Lol

Thanks,

Paul.

[Vorlockfoss]

Right, here is an update.

I replaced the Auxillary Belt Tensioner and Belt, started the engine while the belt was removed, and the scraping noise still occured.

I've also replaced the Cambridge, the Cam Adjuster and the Cam Magnet, but the noise persists.  The engine is running better now and the tickover is slightly lower.  The noise became slowly quieter over 5 minutes after replacing these parts, but persists...

The noise sounds like it's revolving at around 1 - 2 times per second on tickover, so I have to surmise it's timing chain related, maybe the chain adjuster, but metal on metal...?

Thanks,

Paul.

 

[Magnet]

Hello Paul,

Many thanks for the update. I think you have now (unfortunately) eliminated the engine-driven components, and have reasonable evidence that the issue is likely to be engine-internal. 

If it were mine, I would now be seeking an urgent diagnosis at a trusted local independent. 

Kind regards,

Gareth. 

[Vorlockfoss]

Hi Gareth,

That was a mighty fast reply...!

I've been driving it about since yesterday without any problems.  It now drives as it did 5 years ago.  I also have no engine codes at all now, which is the first time for around 4 years...!

When I start the engine the noise I mentioned is quite loud, but as it comes up to temperature it quietens and can only just be heard; while driving I cannot hear it at all.  The noise is definitely not inside the block.  As far as I can tell it's timing chain related, i.e. most likely the chain adjuster, or could even be one of the guides, but less likely.  I'm going to purchase an adjuster, and maybe a chain guide kit, and replace it/them.  It's not a job I relish though, because working on the top with the cam ends is easy as you only have to slide the front forward on 2 long and appropriate bolts, but for the lower end I'd need to either take the front off (oil and water removal), or at least remove the radiator to provide access; any advice on that...?

I'm not going to drive it now until I've checked/fixed, just in case.

Thanks,

Paul.

[Vorlockfoss]

Hi all,

I have an update...  Lol

Loud scraping noise = destroyed Balance Shaft Chain & Crank Cog Teeth.

Remedy = New Timing Chain & Crank Cog.

I did the work myself, which took an age of learning and an age of fixing, but it's all good now. 😁

Thanks,

Paul.

 

Edited January 9, 2021 by Vorlockfoss
Forgot to add who did the work.

[Samuelsjs2]

Hey I own a 2014 A4 S-Line auto with 93k miles it started making the same noise you’re describing, 2 months ago i replaced the timing chain cover gasket because it was leaking and checked the chain, it felt normal tight as it should this noise is becoming more regular. 2 questions how much would a rough estimate be of the job and how do you find a trusted European mechanic or going to the Audi dealer is a better option 

[Samuelsjs2]

Hello I wanted to add that I just added some oil because maybe enough oil had leaked to the point of metal to metal grind would start to occur. The sound stopped and I’ll be getting a oil change this weekend I’ll be back to report 🫡

[Vorlockfoss]

On 5/1/2024 at 12:45 AM, Samuelsjs2 said:

Hey I own a 2014 A4 S-Line auto with 93k miles it started making the same noise you’re describing, 2 months ago i replaced the timing chain cover gasket because it was leaking and checked the chain, it felt normal tight as it should this noise is becoming more regular. 2 questions how much would a rough estimate be of the job and how do you find a trusted European mechanic or going to the Audi dealer is a better option 

Hi,

It is possible that, despite it being tight, it could be at its limit of tension.  How does it run, aside from the noise?  Mine started the same as yours, and seemed to mostly go away once started.  The noise got gradually worse, and louder, and lasted longer, until the balance shaft chain eventually fell off, which stopped the water pump working and caused a breakdown that I needed to be recovered from.

I did all the work myself in the end, as I received quotes of 3 or 4 thousand £ at least (no one knew or cared & just didn't want to do it!).  One garage charged me £350 just to have a look, mess it up, and tell me what I already knew...!  I forgot that around 7 years ago I had the timing chain changed at a garage, which cost £800, and as it turns out, they only changed the 1 main chain, and they caused a blockage on my main oil inlet from the oil pump as they'd used too much sealant to put the chain cover back on...!!

There are 3 timing chains on mine, which I replaced myself.  I also replaced all the guides and the tensioner.  It turns out that I had several issues, which included the chains, guides, tensioner and a knackered inlet camshaft.  As I was trying to diagnose the above I also replaced the oil pump (Audi), the water pump (Inna), various sensors (aftermarket), the oil (2 or 3 times, LiquiMoly), the serpentine belt tensioner (aftermarket), the inlet camshaft (aftermarket, but turned out to be the Audi supplier!), all the cam lifters (inlet & outlet, Inna), the charcoal thingy at the back (Audi), the high pressure fuel pump gasket (it was folded on one corner! Audi)), the pcv valve (Audi), the cam cover (eBay), the water thermostats (aftermarket), the cam bridge (removed the filter mesh! Same as camshaft), the 4 ignition coils (aftermarket high end), the camshaft adjuster & magnet (same as camshaft), the crank bolt (Audi), the serpentine belt (aftermarket), the oil level sensor (Audi), and probably something else too I have no doubt.

It ended up costing me around £1,500 for all the parts (I bought them from Germany and some from Audi), but I didn't need them all.  Although, my engine has run better for the last 2 or so years than it did when I bought it...!

I know that's not what you wanted to know, but that's what I did.

😁

[Vorlockfoss]

On 5/1/2024 at 2:38 AM, Samuelsjs2 said:

Hello I wanted to add that I just added some oil because maybe enough oil had leaked to the point of metal to metal grind would start to occur. The sound stopped and I’ll be getting a oil change this weekend I’ll be back to report 🫡

That sounds bad.  Didn't your engine warn you the oil was low? I'm wandering if adding extra oil simply temporarily disguised the issue...