View Full Version : 05 A6 4.2 knocking noise in head!!!!

09-19-2014, 09:39 PM
So I started my car tonight and everything was fine. I pulled into a gas station about a mile from my work and noticed a significant knocking noise in the head. It is louder at idle the if you give it gas. I have no CEL, misfire codes, or low oil prssure lights. If anyone has a any clue to what it could be please let me know.

09-19-2014, 10:29 PM
Could be several different things... Mind posting something that lets us hear it??

09-19-2014, 10:46 PM
When I leave work in the morning I will post a video.

09-20-2014, 02:23 PM
The intake manifold on the 4.2s are prone to having the runner flap screws come loose internally. That's what it sounds like.

09-23-2014, 06:22 AM
So the car it at the garage and I don't have good news. It seems the timing chain tensioner went out on it. There is no damage to the heads or valves. All of the garages are quoting me right at about $8000. I hate to sell a car with the options it has (almost everyone offered in 2005) for a cheap price but it looks like i have to. Does anyone know one know what I could ask ask for a black 2005 Audi A6 S-line with the following options:

-4.2 V8
-brilliant Black
-Black interior
-s-line package
-cold weather package
-power rear sun shades
-rear parktronic
-voice recognition
-power steering wheel
-adaptive headlights
- and all other standard equipment

The car also has 18" Saachi wheels and tires and come with a set of 19" S5 wheels wheels and tires. Both sets of tires have less than 1500 miles on them.

If anyone has any clue about the value of the car with these options and a bad tensioner, please let me know.

09-23-2014, 09:40 AM
where are you located?

As for the price of the car, well you really just have 2 options: price it as a parts vehicle or the fact that this is a ~10 year old car requiring ~$8K in service, that's what you'll need to take off the price.

FWIW, consider getting it fixed and you'll have a great car for less than a used one.

09-23-2014, 09:57 AM
I was afraid of that... You could put a used motor in there for 2-4k or fix it yourself for about $1500 and 30-40ish hours of your time . How many miles does your car have?

09-23-2014, 10:24 AM
Im in central PA. The car has just over 125,000 on it.

09-23-2014, 10:34 AM
I'm with FormulaElement. Spend the $$ and/or time to get it fixed. You may get $4-$5K for the car as it sits today...

FWIW, there was a local vehicle in great shape which had an engine issue and the person sold it for $4K and they in fact included the cost of transport in the final price.

10-17-2014, 08:46 AM
So just a small update. The garage the car is at ran some sludge cleaner through the motor the see if it would free up the tensioner and it really quieted down the tapping. I am trying to upload a video but don't know to to quite yet. My question is though, do you think a it would still be the tensioner if putting the cleaner though it quieted the tapping down as much as 75%? I dont see how it is possible.

10-17-2014, 09:28 AM
The sludge cleaner is REALLY thick stuff IIRC. It probably got to the tensioner and did a band aid on a bullet wound type of fix. It may have gotten much more quiet, but if you're still hearing noise, that's still slack in the chains that is beating up the guides, chain, and tensioner assembly.

FWIW, the one I'm working on is a 3.2 I picked up in really nice condition for $3500 needing tensioners (maybe more, will know later today after I replace the tensioners). If you're mechanically inclined and have the garage space, I'd recommend doing the motor pull, fixing it, and giving the car a new lease on life. Otherwise you're really going to get plucked selling it. No matter the condition, a 2005 first year that's 9 years old at this point needing a motor pull to be fixed, you're talking probably 3-4K tops. Just an honest opinion.

10-17-2014, 03:55 PM
omg why 8k just to change a Timing Chain Tensioner!? if the heads, timing is not damaged whats the prob.

10-17-2014, 04:49 PM
omg why 8k just to change a Timing Chain Tensioner!? if the heads, timing is not damaged whats the prob.

In case you don't know, the motor has to be pulled in order to replace the timing chains/tensioners.

10-17-2014, 08:33 PM
I would be really careful if the tensioners were noisy and you quieted them down by putting that stuff in there... There's a really high chance of it skipping a tooth and the timing becoming off and all sorts of problems them.