[Surfpilot111]

Hi My turbo (newly installed with only about 1000km) in my Audi A3 2.0tdi (BKD) is whinning (NON-metallic sound...more of a whhoooting sound). Whenever I DETACH the vacuum line of the turbo's wastegate to the solenoid block...the sound DISAPPEARS!
I bought a NEW Solenoid valve block (the one with 6 vacuum lines attached to it) and installed it..but the problem did NOT go away! the whinning sound is still there unless i detach the vacuum line to the wastegate as I did earlier.
I also inspected the impeller of the turbine but they seem to be OK.
I checked for fault codes using my VAGCOM but there was none.

Where else should I look?? Thanks in advance!
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[Fluid]

Well you know it's not the solenoid valves. Maybe it's normal, it's the sound of the new turbo? It could be a loose pipe or hose that came loose after installation. Check all the EGR piping, intake hose piping, and exhaust piping. Depending on what the mechanic touched, it could have come loose.

 

[Surfpilot111]

Yeah..but there is NO power It seems like there is a leak or a solenoid block problem that is causing the VNT to be open and bleed out boost except when I disconnect vacuum line to the VNT actuator, the sound disappears.

 

[chittychittybangbang]

If it's anything like earlier cars it's possible the EGR-N75 solenoid valve vacuum lines are switched. Or some other vacuum line swap or problem. Double check your vacuum diagram and see if the lines, wires, and solenoids are routed correctly.

 

[Surfpilot111]

Thanks for the tip! Will plug in my VAGCOM later..I would appreciate some tips on what to look for. Thanks!

FYI i replaced the Solenoid Valve Block (is this the N75??) and it still bleeds boost and whines. The turbine has been checked and the seals seem to be ok as there is no excessive oil on the impellers and it turns without shaft play just like when it was new 1000km ago. And as I said, whenever i detach the vacuum line to the VNT actuator, the sound disappears. Thanks for the help Chittychitty Bangbang!

If it's anything like earlier cars it's possible the EGR-N75 solenoid valve vacuum lines are switched. Or some other vacuum line swap or problem. Double check your vacuum diagram and see if the lines, wires, and solenoids are routed correctly.

 

[Surfpilot111]

Found out that turbine shaft was slightly bent Replaced turbine and problem gone.

 

[chittychittybangbang]

Thanks for the follow up!