CanAm Eight

My 2012 A8 has developed valve train noise, I think.

Between 2,000 and 2,500 rpm I hear distinct engine clattering. Both during acceleration and steady speed. The noise is subtle, but it is there, I can hear it, and I am in my mid-70s.

The Minneapolis Audi service people have been very responsive to my questioning the sounds, including having a pair of techs drive my vehicle and then another with the same engine. Their conclusion is the sound is normal. The newer 4.2 has a chain driven valve train, and is reversed from my previous machines with the 4.2 which were belt driven.

My work around is to drive in "D" rather than "S" to stay away from the noisy rpm range.

That being said, I am surprised I can hear engine noise on this class of vehicle at 50mph.

Anyone else hearing this, or is it the onset of senility?

Kurt

Ravill

It is my understanding that our 4.2 L V8's have hydraulic lifters.

Those, you'd likely only hear for a second or two on start up. Very unlikely to hear them at operating temperature and under throttle where they are seeing significant oil pressure.

And thank GOD for timing chains.

CanAm Eight

No, the sound is consistent at normal operating temperatures. It does not go away, always there.

Ravill

Active motor mounts?

derfA8L

I really don't think you should hear anything that sounds like clattering when at speed. Yes, you can hear a faint sound when the car is at idle, which is normal, however when accelerating or cruising, you really shouldn't hear anything like that. At least I never did in my last D4 4.2L, nor in my 2008 D3, also chain-driven.

mishar

Can you hear it with opened hood at that rpm? If it is chain tensioner, bad hydraulic lifter, or even bad camshaft you should hear it. I hope you are not one of those regular gas guys? It could be some knocking while ECM is trying to compensate.

CanAm Eight

It is not preignition, The noise is the same under acceleration as steady speed. The focus point is 2,250rpm. I listened with the hood up as did the Audi techs. There is no discernable single point, like a bad lifter or flat cam.

mishar

No discernible single point but is there a certain sound? It may be filtered through the insulation and just get noticeable at the right rpm inside the car, obviously not to all ears. Though I would not relay on Audi technicians. They are not looking for more work. Especially under warranty.