I own 1999 A6 2.8l 5 valve .The motor is making ticking /tapping noise at idle .As i would rev up to 1200 rpms noise got louder then it would go away as rpms climbed.I noticed the Diesel sounding rattle coming from right passenger valve cover, no noise from drivers side.I have replaced all 9 intake tappet lifters and also replaced cam chain tensioner. I started the motor and the ticking is still present at idle WTF! I have run out of leads. Can any one shed some of their knowledge .I am tired of throwing money at this car.Common gurus, I need some advice

 

you may find this to be consoling rather than helpfull. i seem to here thesame sound from my car as well but mine changes in nature becoming rougher as the engine gets to normal opperating temps. at time it would seem to go away. this has been for a while. i want to associate it to my faulty CEL for CAT.

 

gurus ?

 

cam tensioner... There is a DIY on DIY section

 

like i said in my first post,I replaced it with a new cam tensioner .Part was not cheap! and folowed the DIY tutorial precicely.

 

Ooops did not read that. In that case, I think you might have a blocked oil passage going to the head perhaps? The fact that you had to replace all lifters and tensioner might have been caused by sludge. Try seafoam.

 

I did try seafoam and it didnt work .I ran the car for 1 hour evn drove it around to no avail..Flushed oil and replced filter and tried marvel mystery oil,that didnt work either.....I changed oil again after I replaced Cam tensioner and lifters.I inspected Cam lobes and caps and they seemed fine .I mean they did not look damaged at all..I appreciate your help .
Are the oil passages in these motors commonly clogged by sludge ? That thought didnt occur to me .It makes sense, if the passage is clogged to the tensioner..I was getting ready to install new oil pump ....
I dred thinking about tearing it down again to inspect it ...damn VVtiming ..I will remove intake cam and tensioner and flush the hell out of it with carb cleaner or some strong solvent ,Ive even considered diesel....
thanks hxgaser...

 

2.8s are better than 2.7, but there are many cases of sludge on these things. That is one of the reason that I run synthetic, although it is not required. I ran my car about 200 miles with seafoam before changing the oil. Try giving it some time and see what happens.

 

I think i will try one last time , adding some kind of motor flush.Ill take your advice...
Do you think i shoud remoove oil pan and inspect oil pump pick up tube ....Does the screen get clogged by sludge like the 1.8l motors?

 

Could be a sticky carboned up valve that is not closing all the way. Hydraulic lifter can only compensate so much. Compression test done?? Just my a wild a** guess. My 2.8L '98 30V did the same thing occasionally.