mk2sleeper

I have recently purchased a 2004 S4 Avant that comes with an Audi extended warranty until 160k, when ever I have been driving for like more then 20 minutes or so or when the engine is hot, I start to hear this tapping noise from one side of the engine, it sounds like the lifter noise, but the noise goes away when I give it some gas, it might come back after a while and it will go away when I give it gas again.
Is it possible that the oil pump is weak? or could it be the lifters? Is this covered on the Audi extended warranty?? I am new to the 4.2 V8 engines, please help!

mk2sleeper

ok, it's been a week and not one reply.... ?? oh well..... I have been doing some research on the sites and thinking that it could be the oil, I just threw out the new quaker state Q synthetic 10w30 which has been in the engine for only 3 days and replaced it with AmsOil 10w40, I have a feeling most of the B6 S4 prior to 2005 will have problem due to the Audi free oil change, they don't use synthetic oil until 2005 models, seems like all the S4 prior to 2005 uses only convention oil, for those who spended the money to synthetic did the right thing. Most of the oil in the market DO NOT meet the standard from Audi/Porsche/VW. So now I am thinking I have a worn cam lobe or something and I only hear the noise when the oil is really hot... ..

A8CT

There are a bunch of us who have this issue. I have 2 A8's that do this. One has 140k and the other has just turned 100k.

It doesn't seem to get worse with mileage. Only when hot right? No noise when you first start it.
I started a thread about this 3 years ago and no one has found "the" fix.

Just the other day one of the guys emailed me and said tthat he changed to 15w50 oil and the noise is basically gone. Makes sense why there's no noise when cold.

It's not the cam tensioner, oil pressure or lifters. Someone even had the ECU replaced thinking that it was a software issue. Give the 15w50 a try, this might be the answer.

Feel free to email offline and I'll add you to the 5 or 6 of us who have been tracking this issue.

Bob

mk2sleeper

Thanks so much for your reply A8CT, at least now I know I am on the right track on tracking this problem, I might even try mixing some Lucas oil stabilizer to see if it will work better!

A8CT

let me know if it works. I just changed the oil on both my cars so I'll do this next time around

Cpagl7

Yupp! 2001 S8 w/ 70 K started valve "clatter" about 500 miles ago. Dealer thinks it's "a" hydraulic lifter. Dealer estimate to open and replace all lifters on that side just south of $4000. Extended warranty will not cover preventive maintenance!! I am not using synthetic oil. . . . yet. For what it's worth, I had once of those other V-8 German cars with synthetic oil, valve "clatter" developed every 5000 miles, which reminded me to change the oil, using synthetic, the valve "clatter" would disappear for another 5000 miles. So perhaps, there is something to the use of synthetic oil in these engines. FYI dealer and his mechanic say, although it's not great, this is no sign of immediate imminent engine failure; the engine will just fail sooner or later anyway.

mk2sleeper

It has been a week with the Amsoil 10w40 and the sound is totally gone! I have even tried driving the car for 2 hrs straight and still shows no sign of lifter noise, there was an obvious power gain and gas consumption improved a bit, it is now so much more fun driving that 4.2 V8, feels like the engine just woke up again!! woohoo!!

Cpagl7

OK - since I posted on this thread - I changed to synthetic oil (Mobil 10w-40); no luck! I changed again to Amsoil 5w-40, European oil; no luck. I've tried a few additives; no luck! Interesting enough, it purrs like a kitten immediately after the oil change, but within a few miles, the clatter is back.

Cpagl7

After trying all of the above, then some. I had to have the cylinder head changed $5500. Either the oil distribution system was clogged, the alloy was bad, who knows! The dealer did try an oil flush first, but it did not help. Once opened, worn parts were found. Of course my extended warranty will not help because the mechanic could not specify the cause of the problem!

charliemike71

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