Knocking Noise Upon Start Up
 

Hello everyone,

I am just trying to gather some information about who has a rattle upon start up of their engines which usually lasts 1-2 second after which it goes away. The reason I am trying to see who has the noise and who does is because Audi has not put a TSB specific to our cars yet about the noise and I am currently dealing with this concern on my 2004 D3. However D2 A8s have a TSB specific to this concern. Some of you may ask what is shared with the D2's engine compared to D3 engines. With respect to the noise it is the hydraulic adjusters for the variable valve timing. They are the exact same part number for the D2s and D3s. Finally while doing some more research I found a TSB about the VW Phaeton, which shares the same 4.2L base engine (same part number) as the D3s. In the forum post, which I will link below, it mentions two peoples noise showing up after a timing belt job, invisiblewave is the member of interest if you care to read the post. So besides saying if your car has the noise or not, if you can remember when it first showed up that would be great.

VW Phaeton link: VWVortex.com - TB: Camshaft Rattle when Engine Started (4.2 litre V8 only) - includes TB 15-06-01

Here is the VW TSB:
https://cimg2.ibsrv.net/gimg/www.aud...94a409b56d.jpg
https://cimg3.ibsrv.net/gimg/www.aud...0cc82b3f1c.jpg

Jarett

It's normal
 

So what are you trying to determine? If it's normal or not? That VW TSB tells you all you need to know.

Mine will do it if it's not been started for several days, but I know what it is, it's cause, and the fact that it's a perfectly normal characteristic so I don't concern myself with it. Virtually all engines with similar features do it.

I am trying to determine if it is normal or not with respect to what my engine does when starting. The noise occurs almost every time the engine starts after it sits over night or is cold, and sometimes very lightly after a short drive and rest for 30 mins to 1 hour.

What you describe sounds normal to me.

I would say normal. Some leak down faster than others. My Passat 1.8t does it even if only shut off for 15 minutes. That motor has about 15k on a rebuild and the tensioner/adjuster was replaced with a brand new part during the rebuild.

I've never heard my A6 2.7t do it even when sitting for weeks and it has about 95k miles.

My A8 will do it if left sitting for several days and it has about 136k miles.

Normal. When it seems more frequent, it usually occurs as my oil approaches 10,000 miles of service. Maybe consider changing to a 5W series of motor oil.

Completely normal. Audis have been doing this since at least the 80s.

This is my 4th D3 and it is normal as my previous ones did it too so I can tell you from experience. As long as it achieves the right oil pressure and goes away in 2 seconds I'm not worried about it. It's noticeably less noticeable when the ambient temp is cold like below 40 degrees as the oil is thicker. Good post that you started.

Yep. Most of the times I have timed the noise it lasts at most less than 2.5 seconds. Their has been only a few times where it has gone 2.5 seconds or slightly above and, to my knowledge, never gone above 3 seconds.

[QUOTE=jlbell;24719466]Yep. Most of the times I have timed the noise it lasts at most less than 2.5 seconds. Their has been only a few times where it has gone 2.5 seconds or slightly above and, to my knowledge, never gone above 3 seconds.[/QUOTE

Yep. Every car is different. My dad has an 04 D3 with only 47k miles on it and no matter how long it sits it never does that, nor when it's warmed up.