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170 TDI odd engine noise - now with pics - turbo?

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by eddscott, Jun 15, 2012.

  1. eddscott
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    eddscott Member

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    [Jun 15, 2012]
    My A4 has developed a new noise.

    On boost and on load there's an odd constant tone. The tone changes when I come off the throttle and goes completely.

    If I just rev the engine it sounds completely normal. But on load as the boost comes in this tone appears. It's not the DV noise as its constant on load.

    The car has had the DPF and EGR removed with new pipes and been mapped to suit but not too aggressive. One question, if the EGR cooler pipe has been blanked off wwould that cause back pressure on the turbo vanes?

    Another small issue is that on a long drive last week the low oil light came on so I stopped at a Halfords and bought some Halfords own brand 5w30. Although it is a 170 it no longer has the DPF so I thought the oil would be ok. I only put in about a litre. Not sure if that has anything to do with it.

    As an aside it's still using coolant too. Not much but it is going somwwhere.

    Bit fed up now. It's almost every week a new issue appears. Might put back to standard and get rid.
    Last edited: Jun 16, 2012
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  3. eddscott
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    eddscott Member

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    [Jun 16, 2012]
    One of my headlight bulbs went so off to Halfords for new ones - it was raining so paid the extra to get them to fit it. Got home and noticed the lad hadn't fitted the bulb properly - what a surprise.

    So, in order to get a better view of the headlight I took off the air box and turbo hose.

    This is what I found

    [​IMG]

    Took the bottom clamp off and this is the state of the pipe. It is quite wet here - could this be where my coolant is going?

    [​IMG]

    The pipe coming from the top of the engine into the inlet is full of this stuff

    [​IMG]

    Whilst I had the pipe off I decided to see if I could move the turbo shaft - I can wiggle the shaft up and down a couple of mm, less side to side and barely noticeable forward and back. Does this mean the turbo is about to go?

    I had a good look at what I assume is the MAF sensor in the airbox and it looked fairly clean - was expecting to see it all gunged up but its not.

    The noise only appears once the car is warm - no smoke, no loss of power. It doesn't sound like the rattle clatter of "blown TDI turbo" that you find on Youtube.

    I'm very concerned that the removal of the DPF and EGR and mapping has done this or whether its just coincidence and bad luck on my part. If I have to get a new turbo I don't want it to happen again so maybe put back to standard?

    I just can't help thinking that blanking off the EGR pipe from the EGR cooler has somehow damaged the turbo. If the cooler pipe has been blanked off wouldn't there be higher pressure in that area? If so, is it possible that the higher pressure has forced some of the coolant into the turbo in some way?

    Please help chaps!
    Last edited: Jun 16, 2012
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  4. outsideline
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    outsideline Member

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    [Jun 16, 2012]
    pm'd you mate
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  5. gradwells
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    gradwells Member

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    [Jun 16, 2012]
    Share the knowledge please , I have one of these and I am getting paranoid after reading these forums !!
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  6. outsideline
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    outsideline Member

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    [Jun 16, 2012]
    i cant begin to write all what i have said to edd on the phone mate lol.

    what do you want to know lol????
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  7. matthew999
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    matthew999 Member

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    [Jun 16, 2012]
    Spill the beans! Haven't you both had the same stuff done to your cars?
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  8. eddscott
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    eddscott Member

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    [Jun 17, 2012]
    We went through quite alot of stuff really. Hugely appreciate the chat!

    I was fairly convinced things were going south on the car but fingers crossed it is going to be OK - reading too many horror stories on the net I think.

    My main concern is this new noise thats appeared. Not too sure what it is but as I have had my EGR and DPF removed I still have the EGR cooler fitted. Going to take it off altogether and see what happens. I've read (more reading!) that the cooler can leak coolant so with hope removing the cooler might remove the odd sound and stop the coolant from disappearing.
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  9. Andy-R
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    Andy-R Member

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    [Dec 11, 2013]
    Just stumbled across this old thread and sounds like the same issue I'm having albeit my car hasn't had the dpf removed, can anyone give any more info than what's above, did you get it sorted in the end Edd? Cheers.
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