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My 2002 Audi A4 with 3.0 with manual trans. is noisey on start up as if it has worn valve lifters. Maybe there is a plugged oil line to the upper head?
The dealer, Prestige Audi, kept it over night, started it cold, and said this is normal. I have had GM V6 engines with nearly 200,000 kms on them that sounded much quieter than this engine with 52000 on it.
Would an oil additive help clear this or help lubricate whatever is running as if dry of oil?
It does not sound right to me.
Are Audi V6's just noisy?
Any comments would be appreciated.
 

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One possibility....

I am having an issue with my 3.0V6 that sounds similar. It rattles on cold starts and also at 3-4000 rpm. Sounds sometimes like someone left a metal bucket of bolts on top of the engine at its worst.
Turns out that there is a valve (intake manifold rotary change-over valve) that runs right through the inlet manifold in the centre of the V and this rotates to change between short and long induction paths at different rpm. The spring betweeen the actuator (2 vacuum cylinders on the front of the engine) and the valve breaks causing the valve to rattle. This then damages the nylon seals in the valve, causing induction leak between cylinders which eventually when it gets bad gives misfires and loss of power.
If this is your issue, its easy to check, pull the plastic cover off the front of the engine, and take the vacuum cylinder module off, (2 torx bolts) and see if the spring is intact.
If you do have a problem with valve lifters, then this also helps diagnose, because you can then slide the valve out a little, not all the way because the radiator is in the way, but if it is covered in wet oil, then the seals on the valve lifters are failing and allowing too much oil back into the inlet manifold.

Don't allow Audi to fix it because there response is to change the whole manifold casting (£900 for the parts + labour!!) If your seals are OK, just get a new spring and the noise goes away, otherwise change the valve assy (£150) but be prepared for high labour because you need to take the manifold off or the radiator off to get the long valve out of the manifold.

Lookup VR6 rattle to get more info as these engines suffer from the same thing.

Hope this helps

Andy
 
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