Ok I have been a audi lover for the past 4 years now. I just purchased a 1997 Audi A8, the guy who sold it said it had a engine knock. So i figured i will replace the engine. But i want to make sure thats is the main issue for the noise.

I brought my cousin with me for him to here the sound and lend his opinion. Upon listening to the engine he advised it sound like a front end knock. But the battery was dead too and my cousin advised to replace the battery due to the owner telling use he jumps the battery alot. I figured he did this cause he just had the car sitting.
I noticed the check engine was on as well. I paid for the car and we towed it home. I was reading reviews of using lucas to quite the knock, so i went to pep boys brought a new battery and a bottle of lucas. I retured home put in the lucas and changed the battery. I started the car and the knock was there, i figured i would let it run to see if the lucas would quite the knock, IT DID'T. So i drove the car around the corner to auto zone to check the engine light. pon turning the car off I herd a histing sound from the left side of the car. needless to say auto couldn't check the engine light.. So i got back in the car and started it up and now the egine light and battery light was on. And as i was driving the car started to shake, tick and knock for about 2 mintues. it then stop I parked the car and contine to let it run for 15 mintues checked to see if the car was over heating and it didn't. So i turned the off and herd that histing sound again.

Im so lost I've been reading online and someone posted that the alternator can be confused with engine knocking.... Could someone help me narrow it down so when I take the car in to be checked i can tell him were look.

 

Well if he's been jumping the battery then that generally means there's a charging system issue. Either the alternator, battery, or both are bad. My advice would be to have the alternator checked at Pep Boys and to also head over to Advanced Auto and buy an OBDII scanner. I got mine from them for $50 and it was money well spent. Check your codes then write them down and check them here: http://www.obd-codes.com/trouble_codes/ Any code that starts with a "0" right after the "P" will be a general non-brand specific code.

 

Wilkommen to the froums

be sure to spend some time in the A8 section, lots of good knowledge over there.

it's pretty difficult to try and diagnose your problem over the internet. like airguard suggested, the first thing you should do is get the codes read. I know you tried, but it is something that really needs to be done straight away.

good luck with your car

hvae fnu