Audi a3 1.8 BZB Mettalic Rattle Noise

[Harrya3]

Hey guys, new to the forum. As the title says the past 4 months i had been getting a strange mettalic rattle noise which only occured after i drove the car very fast with multiple accelerations etc. or at high speeds, in which case after going slow at low rpm from 1st to 4/5th gear i would get this rattle noise occuring between 1.5-2.5k RPM's. The noise is VERY loud and audible with windows up/down and to surrounding cars. The past week however, after driving the car fast to recreate the noise for the mechanic, who sais it was a PCV and we changed it but nothing worked. the car has been doing this loud rattle at cold start for 5-6 seconds which then stops. My question is, would the timing chain make noise only after been driven fast?? or is this a symptom of something else? i can't get a straight answer from any mechanics and i don't want to be changing the whole timing chain system only to get the noise again... i am attaching a video from the rattle which is audible at cold start. 

https://streamable.com/nfawg7

Main question is if it's possible that the timing chain would rattle at low rpm's only after car was warm and driven fast?? this would stop after driving normally for a few minutes (5-10 mins) or is this a combination of a bad turbo and bad timing chain... 

 

any answers would be appreciated, could this be turbo related??? 

[cliffcoggin]

A few questions first Harry. What do you mean by PCV? Which engine is it? How many miles has it done? Does it have a service history?

It's impossible to be definitive about the rattle without getting close to the engine to locate the source of the noise. It could indeed be the timing chain (has it and its tensioner been renewed,) or it might be excessive valve gap (depending on which engine it is). I think it is unlikely to be the turbo. In your place I would use a stethoscope on each part of the engine to locate where the sound was loudest. (That's not a medical stethoscope, it's a mechanic's equivalent. They look similar but the mechanic's version has a rigid steel probe instead a rubber cup.)

[Shauny-s]

I'm having a similar problem with my tdi mate and I've narrowed it down to the cam to cam chain tensioner 😬

[Harrya3]

Hey guys and i apologize for the mistake as i was away for the weekend. The car was at the mechanic who changed the Camshaft position sensor, which did nothing. Following this he quoted a large sum for the change of the timing chain kit, i have now moved the car to my other mechanic and i will be changing the timing chain kit. The car is an audi a3 8p model with the 1.8 TSI BZB motor and it has 85.000 Km's. I've read that the timing chain tensioner on these is prone to failure with catastrophic results. Let's hope that it solves the issue... I will update you Shaun once completed. 

[cliffcoggin]

Harry thanks for the update, few bother to do so after the initial question.

Do let us know the outcome of the repair.

[cliffcoggin]

Shaun.

If your engine is like mine it will have a cam belt not a chain. Belts can fail without warning (unlike a chain,) so it is recommended to renew every 70000 miles. It is usual to renew the water pump at the same time because of the difficulty of getting to it.

[Harrya3]

Good morning Cliff, spoke with the mechanic again he says that he's hearing the turbo and not the timing chain.. Could be right, at the moment i have now idea. However, seeing as that the noise on cold starts last over 10 seconds and that it rattles again when speeding, he might be right. after all timing chains are supposed to last and the car has 85.000Km's... I believe that the timing chain tensioner issues did not affect 2007 BZB motors. Will cold start it once more to confirm any suspicions. 

[Harrya3]

Wow, i actually came across this guy who had a manifold issue that sounds exactly like mine... Let's hope i do not need to remove the whole engine to remove a broken screw 😕 
 

 

[cliffcoggin]

Sorry Harry, but to my ears that sounds quite different to the first recording you posted. However you are the only one who can hear it for real so you will have to make your own mind up. Ultimately the only way to be sure what is causing the noise is to dismantle and examine. The only certainty is that it will be expensive.

[Harrya3]

Morning Cliff, you where right the sound is not the same. We did open up the timing chain and saw that it was in good condition (only minor stretching) i did end up chaning the whole Kit since we did the labour anyway and he told me that my car had the old timing chain tensioner P/N and we replaced it with the updated one, tomorrow i will get the car but i dont think the sound will subside as it's probably turbo related after all

[Harrya3]

Hello audi owners, for the people who will be reading this forum post and having similar issues like me, please note that after a lot of money and time spent (feel stupid saying it).. my issue was actually worn exhaust manifold bolts. I removed the turbo, re-thread 4 out of 9 bolts and used turbo specific screws i bought and the car is perfect now. The symptoms where at first after high boost or fast drives on my car, there would be a rattle/rustle noise at low rpm from 1st to 4th gear (not as much on 5th or 6th) and eventually upon cold starts the car would make a rattling noise similar to the timing chain but for a much longer duration. Throughout this ordeal i end up changing the following which might cause a similar noise fyi:

Timing chain (i did have the old tensioner P/N so i did not regret it)
Inlet manifold actuator control (sometimes the flappers might cause a rustling noise, however you can test them through VCDS)
PCV Valve (also causes a rustling, boost loss noise rarely)
Camshaft position sensor

i also suspected a loose wastegate flapper and i bought the Clip from eBay
 

Hope this helps the trouble for someone else!

[cliffcoggin]

Glad to hear you have solved the problem Harry, though sorry about the hole in your wallet. I would never have guessed at exhaust manifold bolts in a hundred years. Had they stretched or were they not torqued enough?

[Harrya3]

4 of them had stretched, the rest where fine. Indeed it was peculiar especially considering that the car in total had 80.000 km's and less than 10k with a tune and the RHF turbo (i suspsect a mistake by the guy who installed it).. At least i solved it and i'll be getting back what i spent sometime soon with all the gas i'll be saving now 😄