A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D3 > D3 - Engine Bay

D3 - Engine Bay Everything under the bonnet

Reply
 
Thread Tools Display Modes
  #1  
Old 7th May 2019, 06:47 PM
Duff3103 Duff3103 is offline
Junior Member
 
Join Date: May 2019
Location: Edinburgh
Posts: 21
Default 2006 4.2 tdi noise on acceleration

Hi all, i bought my d3 in november last year, on road test i never noticed a noise as the boy was blethering on about how well built these cars were bla bla bla, anyway i noticed the next day when i had the window down as i never really gave the car any boot, upon acceleration there is like a high pitched squeal which i have a suspicion is the turbo.

Iv fixed a couple of minor faults on the car already ie short to earth to the fuel metering valve on the high pressure pump, a glow plug, both upper suspension arms on passenger side as well as the front drop links to cure a knock and reset the pad thickness on the rear as the pad light was on but the pads were new.

This fault however im baffled by this one as i simply cannot find the location of it although its in the engine bay, iv had the exhaust off from the dpf's back in case there was a leak in the system somewhere but was certain it wasn't that, iv had the air filters off on both sides to see if the noise will replicate from there, iv smoke tested the exhaust and intakes for any leaks as i thought it could've been a minor leak on an intercooler or intercooler hose but nothing showed up there either, although on searching it seems the a/c clutch on the compressor is knackered as well as the radiator leaking slightly at the passenger side

im hoping by posting a short video of the fault one of you might have had the same fault and are able to pin point the exact fault

thanks
Attached Files
File Type: mov IMG_5141.MOV (6.88 MB, 407 views)
File Type: mov IMG_5142.MOV (4.77 MB, 378 views)

Last edited by Duff3103; 7th May 2019 at 06:51 PM.
Reply With Quote
  #2  
Old 8th May 2019, 08:06 PM
snapdragon snapdragon is offline
Senior Member
 
Join Date: Nov 2011
Posts: 1,669
Default

I have a 3.0TDI, but it doesn't sound a million miles away from a sound I had which turned out to be the bearing in the A/C compressor pulley. What is the scope of cutting your aux belt and quickly testing (before it overheats) and then putting a new belt on?
Reply With Quote
  #3  
Old 8th May 2019, 09:51 PM
Duff3103 Duff3103 is offline
Junior Member
 
Join Date: May 2019
Location: Edinburgh
Posts: 21
Default

Well that if it is that could be a relief as I have a brand new compressor waiting to be fitted as it’s creaking and cracking whilst it’s running, I’m praying you are right that’s for sure
Reply With Quote
  #4  
Old 22nd May 2019, 01:47 AM
Duff3103 Duff3103 is offline
Junior Member
 
Join Date: May 2019
Location: Edinburgh
Posts: 21
Default

So i replaced the a/c compressor tonight and recharged the air con system so i finally have cool air and the cracking creaking noise from the faulty clutch pulley is now gone...........but

The high pitched noise is still there, which i didn't think this wasn't related to the a/c but was worth a shot as it needed done anyway, so back to the drawing board, I'm still thinking turbo myself but its hard to pinpoint from the drivers seat where the noise is coming from considering i can only get the noise to happen whilst driving next job is the radiator and headlight washer hoses from the bottle as they have broken up with age so its capped off at the pump just now to stop it leaking
Reply With Quote
  #5  
Old 22nd May 2019, 11:41 AM
snapdragon snapdragon is offline
Senior Member
 
Join Date: Nov 2011
Posts: 1,669
Default

Oh dear, well I suppose it could be any of the pulleys, can you pop the belt off again?
It could be turbocharger but I would think you would be able to hear it is coming from that with the bonnet open. What about the vacuum pump for the brakes etc...?
Reply With Quote
  #6  
Old 22nd May 2019, 10:25 PM
Duff3103 Duff3103 is offline
Junior Member
 
Join Date: May 2019
Location: Edinburgh
Posts: 21
Default

To me it’s turbo as obviously sitting stationary you cannot gather boost pressure, the only way I can replicate the noise it under load and when the turbo is spooling, iv managed to replicate it slightly by the revs alone but only if I click it into neutral whilst above around 10mph where the revs will go past 4000rpm, I’ll be much happier with the car once this noise is fixed, it’s the only thing that’s really bugged me since day 1
Reply With Quote
  #7  
Old 16th June 2019, 05:21 PM
Duff3103 Duff3103 is offline
Junior Member
 
Join Date: May 2019
Location: Edinburgh
Posts: 21
Default

So I stripped the car down for the turbo to find the company had sent the wrong one and someone had given the engine support bar to another garage so ended up not changing the turbo 🙄

Whilst it was stripped it had a new radiator and a/c condenser as they were leaking aswell, I blanked the turbos and carried out a smoke test on the inlets and found a leak at the right bank swirl flap manifold, the spindle as it comes out the manifold had worn away the plastic so was leaking past, so I purchased a delete kit from a polish company and fitted the kit along with the brackets for the motor to fool the ecu into thinking they are still fitted. I also carried out a tunap clean on the inlet and decoked the cast inlet manifold as it was choked on the egr channels, surprisingly a lot of carbon come from both the ports and cast manifold itself, it has made a noticeable difference in smooth running and noises it defo runs a lot quieter and feels smoother to drive but obviously the noise still lingers so thinking of just living with it for the one being.

Defo something I would suggest is the inlet clean as at 122k miles it was fairly choked up and found more so the swirl ports were cokes compare to the no flap assisted port. Also changed the gears for the throttle valve on the left bank as they had worn down and was apparent when operating by hand. So regardless of the noise still being there there has still been progress on it jist not all the progress I’d hoped for 🙄
Reply With Quote
  #8  
Old 17th June 2019, 03:09 AM
H-M3 H-M3 is offline
Senior Member
 
Join Date: Feb 2016
Location: london
Posts: 865
Default

Well done mate and good to see you can fix your own cars. I wish I had your skill set, would save fair bit of £.
__________________
A8L 3.0 TDI sport executive 2014.
Audi A2 1.4 petrol 2002

SOLD. Audi A8L 4.2TDI Silver 2006

Seat Ibiza 1.4tdi Eco 2008 Silver (£0 Tax)sold

NO VCDS rely on Neeldub
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 09:13 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.