knocking noise in A4 TDI Engine

[Paulw]

I've got a 98 A4 B5 TDI (AHU 90bhp engine) with 70k on it. Just recently i hear the engine making a bit of knocking noise at idle, this is not consistent and happens immediately after start up, clears up for about a minute and then continues.

The engine just doesn't sound as smooth. Any thoughts / advice would be appreciated!?

 

[vw754]

with engine at idle slacken 1 injector see if it go's quiet,if not retighten and do next injector,and so on.if slackening of of the injectors go's quiet,you have injector knock.

 

[golisago]

I've got a 98 A4 B5 TDI (AHU 90bhp engine) with 70k on it. Just recently i hear the engine making a bit of knocking noise at idle, this is not consistent and happens immediately after start up, clears up for about a minute and then continues.

The engine just doesn't sound as smooth. Any thoughts / advice would be appreciated!?

Hi there Paul.........have you by any chance had a timing belt put on recently or any major work injectors etc.........it does sound as if your timing is out.....and if it is noisey because of a belt change it means that they didn't quite get it right and the cam/timing is out and slapping some what.

 

[Caesium]

if the belt timing was out then the engine would run rough throughout its rev range, it may be a hydraulic tappet charging up with oil, most likely.

 

[golisago]

Paul actually hasn't said if it does this if it makes a lowder noise at higher rpm's or not.......i remember i had the very same thing happen to me when i used fully synthetic in my 1Z motor....changed it out for some Castrol GTD and it stopped the tapping .