I recently had my secondary air injection system cleaned. But I still have this strange rattley/Grindy noise coming from the engine could anyone tell me what this sound possibly could be?

 

Does it sound like this?

 

The sound has been bothering me so much and I can’t put my finger on it

 

hello I believe my Audi is having similar problem / noise coming from my motor . Was wondering what was the cause or issue for this to happen ?

I have a 05 A6 3.2 (3.0l) Quattro

 

In my case it was because the upper timing chain tensioner has failed. You should stop using the car to prevent further damage.

 

It does sound like failing tensioners... or the vacuum pump has a leak and draining the oil each night out of the pump and it can make a similar sound on start up when it’s dry. Takes a few seconds and it’s full of oil again.

 

Keli,
I'm trying to figure out what is going on in your video. The sound was gone the next day. So, that means you fixed it? I doubt you fixed it in one day. LOL. Have you fixed it yet? I am still monitoring mine tensioners. I checked them today and I am getting readings between 4.5 and 5.0 combined for each bank (example Bank 1 intake + Bank 1 exhaust ) while at idle. When I rev it up and hold it at 3500 or 4000 RPMs, the numbers go up to 6.5 or 7.0. Is it normal for it to do that? If the tensioner was functioning perfectly, would the numbers hold constant even when revving it up like that or are they expected to increase when you revv it? I'm trying to figure out if I should be concerned yet.

My rattle is only occasionally on cold starts and only lasts a second or two. It is NOTHING like how yours was. I noticed that your numbers were negative numbers. Why is that? Is that better or worse than positive numbers?

Thanks. Glad you are well. I saw your reply to my post on the C7 forum. That car is doing well. I just need to change the motor mounts (common problem with that platform)

 

This video is the last of a series of videos. I opened up the engine and replaced the cam girdle gaskets, resealed the cam girdles and corrected timing by placing the cam girdles back with the camshafts locked on time into them, replaced the upper timing chain tensioners, resealed the upper timing chain covers, replaced the valve cover gaskets, replaced the spark plugs, changed oil filter and engine oil.

This video showed me starting the car for the first time after doing the job. I believe the rattle is expected the first time. It then stops and does not rattle again which I wanted to show in the video.

Before doing the job, the chain noise was similar and wouldn't stop. It turned out both my tensioners were damaged and bank 1 upper timing chain jumped a tooth or two.

They say the safe limit is 9 so you should be fine but you are getting there. When I revv the engine the values fluctuate also a bit.

Your engine shouldn't rattle at all. If it does occasionally, there has to be a problem. If you never replaced the upper timing chain tensioners, you should plan on replacing them. I believe if the tensioners are starting to fail, it means you need a bigger maintenance involving replacing a few gaskets and o-rings while at it. A leaking engine and poor oil quality is what kills the tensioners. This is a thread that shows all I did to stop the leaks and how I corrected timing and replaced my tensioners: https://www.audiworld.com/forums/a6-s6-c6-platform-discussion-58/fixing-oil-spark-plug-other-engine-oil-leaks-3-2-a-2987300/

It seems the C6 is a more stable platform than the C7.