It's still knocking

Aidris

New Member
Good day gentlemen,
Either I'm being rickrolled by mechanics or I'm really unlucky. The deal is that I've rebuilt my s3 8p 2009. Cost over 4k €. New pistons, chains, tensioners. Literally everything new from engine block. Car drives smooth as butter. But the ding dong is that car still rattles when cold. To specify, after cold start settles down. Metal to metal. Dissapears when warm. Does anyone have any clue what could it be? Because soon I will identify as kilometers per second if the problem persists.. HELP!

EDIT: about the sound: rattle matches the revs. From idle to about 1.4k revs, then dissapears as you rev higher. Clutch in clutch out no difference. As car warms up the rattle becomes irrational, it knocks it does not then again until goes silent..
 
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SootySport

Registered User
Alternator or a/c compressor pulleys loose or touching something?
 

SootySport

Registered User
Need to isolate anything outside the engine first before you start opening up the the engine itself. I would remove the auxiliary belts and start the engine to rule out the rotating parts.
Using a makeshift stethoscope may also pinpoint the noise. If you still can't find the cause of the noise then you would have to start looking inside the engine.
 

Aidris

New Member
Need to isolate anything outside the engine first before you start opening up the the engine itself. I would remove the auxiliary belts and start the engine to rule out the rotating parts.
Using a makeshift stethoscope may also pinpoint the noise. If you still can't find the cause of the noise then you would have to start looking inside the engine.
Actually I'll try to remove auxiliary belt as it just can't be the engine. All parts have been replaced, you name it. Heard it could be vacuum pump or fuel pump or even manifold flaps. But will definitely start with auxiliary belt
 

SootySport

Registered User
I know it's a pain in the neck trying to find these noises. The HPFP cam follower can make ticking noises when worn, worth changing that. It's a cheap part and easy to change.
 

Aidris

New Member
Update on rattle battle:
After several checks and many different services, none could locate the source of rattle, everyone guessed either hydraulic lifters or cam chain and tensioner. Both brand new. Really frustrating. Funny thing is that on 5w40 rattles more often than 5w30. Could oil pickup pipe impact this? Since it's only thing not checked. I'll upload video of rattle tomorrow.
 

nluk100

Registered User
Did you not replace the pickup pipe when you rebuilt the engine? This known to block oil flow and cause a ticking noise at low revs / oil pressure?
 

Aidris

New Member
Did you not replace the pickup pipe when you rebuilt the engine? This known to block oil flow and cause a ticking noise at low revs / oil pressure?
Exactly at low rpms. Oil pressure was checked. Within limits. Could be cold oil doesn't get through pipe as fast as it should?
 

SootySport

Registered User
Why use 5/40? 5/30 is the recommended grade isn't it?
 
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