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Loud turbo whistle - is something wrong?

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by s-line stu, Dec 20, 2008.

  1. s-line stu
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    s-line stu Member

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    [Dec 20, 2008]
    Hi Guys,

    After some advice - noticed today that the turbo whistle on boost has got very loud.
    Well I'm assuming it's the turbo as it coincides with when it's on boost. Any ideas as to what might be causing this - am I in for a heavey bill in the near future or could it just be that somethings just come loose?
    The car is a 2004 1.8T (190) with a custom code map and 29K on the clock.

    I also seem to be losing coolant but only when I use the car - it recently sat on the drive for a week and the level never moved but since I've been driving it again it's gone below min. Don't think this has anything to do with the turbo noise but thought it was worth mentioning.

    Thanks,

    Stu
    #1
  2. Siena
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    Siena Active Member

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    [Dec 21, 2008]
    Your turbo whistle could be normal, possibly you have a boost leak, whereby the whistle becomes more pronounced than normal.

    First thing to do is get a boost-leak check, and rectify as needed. Boost leaks will make the turbo work much harder, dependent on severity, and could thereby shorten turbo life.

    I'm also inclined to believe your coolant loss is unrelated.
    Most common sources of coolant loss are a faulty expansion tank cap, or a cracked expansion tank itself.

    They tend to crack at the seam, and are usually not visible.

    Another source of leaks are the heater core, but given the age of your car, I'd say that's very unlikely - not even common on high-mileage B5's.

    Water pumps could also leak, but again, given the car's age and mileage, not very likely.

    I'd concentrate on the cap and expansion tank, both relatively inexpensive. A new expansion tank comes with a cap too.
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  3. s-line stu
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    s-line stu Member

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    [Dec 30, 2008]
    Been to Stafford Audi today - they say there is no boost leak from the turbo pipework so it's the turbo itself - £800 supply and fit!!!

    Last thing I wanted to hear with a recent redundancy as well! Will get some other quotes first as they are unlikely to be the cheapest.

    Coolant loss was unrelated and the blead pipe screw was re-tapped and the system pressure tested for £69.

    If anyone knows a decent place in the midlands for turbo replacement please let me know.

    Happy New Year,

    Stu
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  4. J7USS
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    J7USS Shuddup Foooool!!

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    [Dec 30, 2008]
    Turbo already??
    I take it your going for a 2nd opinion...
    Im in leicester, Ill have a dig through my contacts and get back to you mate.
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  5. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Dec 31, 2008]
    i really cant see it being the turbo with only 29k on the clock....

    Can you describe the noise? is it a hiss? whine? screech?

    Have you fitted a free flowing air filter or aftermarket induction kit? Do you notice any loss in power? Did the noise suddenly get louder at some point?

    It is possible that a leak could kill the turbo, the turbo has to work harder (ie spin faster) to maintain the desired boost pressure as some of its leaking out, more boost (ie your remap) means the turbo would have to work harder still as the higher levels of boost usually means that more leaks out, i also have to say i wouldnt trust audis diagnosis of it not being a boost leak, ive heard many stories of B5 S4's being checked over by Audi as "spot on" when infact they do have boost leaks...
    #5
  6. Chris79
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    Chris79 On my 3rd A4! RS4 next???

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    [Jan 1, 2009]
    That price seemed cheap - especially for a dealer. My wife needed one for her 130 tdi golf, loads of smoke and no power, turbo also sounded like a bag of spanners, vw quoted 1200 fitted inc recon turbo. Bought a remanufactured one with new core, cost about 450 exchange and 150 fitting.

    Work done in Nottingham they said it was time consuming on that car, I expect its easier on a longditudinal engine.

    Chris
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  7. J7USS
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    J7USS Shuddup Foooool!!

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    [Jan 1, 2009]
    I agree with Aragorn. Defo get a 2nd opinion.

    Audi take too many guess shots IMO. Ive had some near Pocket burning experiences with Main Dealers before - Thanks God this Forum is here because the guys on here saved me a whole heap of cash.
    #7
  8. s-line stu
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    s-line stu Member

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    [Jan 1, 2009]
    Thanks for the feedback guys - in response to Aragorn's question it is more like a loud whistle (like when you whistle through your teeth) when on boost. In the past it's just been more of a woosh rather than a whistle and was not that noticable from in the car which it is now.
    The car drives fine and there's no loss of power which is why Audi recon it's not a leak as they say I would notice a drop in performance if it was.
    Other than the remap the car is standard - no induction kit or anything and nothings been done to the car recently that could account for it.
    I think your both right about a second opinion and I'll probably take it to Midland VW at Cannock as they did the custom code map and seemed to be pretty knowledgeable.
    I'll post what the outcome is - fingers crossed it's something less expensive!
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  9. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jan 1, 2009]
    well the point is that with a leak, your pushing pressurised air out a small hole, just like you do when you whistle with your teeth ;) hence you'd expect to hear a loud hissing/whistling noise... The engine also wont usually be down on power, as the correct amount of air does reach the cylinders, as the turbo just spins faster to replace the air thats leaking out, it may run a bit rich though as unmetered air would be leaking out although this might be taken out by the lambda adaption...

    Not sure where your from, but it might be worth taking it to a specialist like MRC rather than another dealer to get some more informed advice. I tend to find that modern dealers just look at what the computer says and then fit parts, right or wrong. If the computer doesnt know then theres lots of head scratching and part replacements at your cost.
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  10. A4 TC
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    A4 TC 1.8T quattro sline

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    [Jan 2, 2009]

    All right mate,
    same thing happened to my car and it had only done 12400 miles with only a remap done to it! Heres a link to one of my previous threads about it http://audi-sport.net/vb/showthread.php?t=45027, thank god it was done under warranty and there was only 2 days left of it!

    Hope this helps mate!
    #10
  11. docurley
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    docurley Moderator Staff Member Moderator

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    [Jan 2, 2009]

    I have found that the K03's tend to only last around 140k if treated with some sort of love but as most know early life of turbo cars are with owners that don't have a clue and have reduced the life of the turbo due to simple neglect of the basic turbo warm down procedure. So based on that a Turbo going at 120k would not be surprising, or the other thing was that is was easier to just swap out the turbo than find the true problem when Audi looked at it.

    I would agree that it is very unlikely to be the Turbo at fault here and a leek is more then likely the problem which a pressure test would confirm.
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  12. s-line stu
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    s-line stu Member

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    [Jan 2, 2009]
    Once again thanks for all your thoughts, I am inclined to agree that it still seems like a boost leak to me especially following Aragorns posts as I have also noticed a slight dip in fuel economy as well. On a steady motorway run I always got 35 - 39mpg where as recently I've been getting nearer 28 - 32mpg which could well be something to do with it.
    I'll take somewhere else next week for a second opinion.

    Stu
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  13. J7USS
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    J7USS Shuddup Foooool!!

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    [Jan 2, 2009]
    JabbaSport near Peterborough are Good at their stuff!!
    #13
  14. evilscotsman
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    evilscotsman Space Cowboy

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    [Jan 2, 2009]
    its a shame they dont fit the car with a factory boost gauge! Never seen a turbo car before that didnt have one as standard till the audi, even a 25 year old starion turbo my brother in law had last year.

    At least then you would see any changes.
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  15. J7USS
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    J7USS Shuddup Foooool!!

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    [Jan 2, 2009]
    Thats right Evil they come in very handy. Just as long as you keep your eyes on the road more.ha!
    Your right though, I think all Turbo'd cars should come with a standard gauge.Even my old Ren5 and Uno turbo had one...
    #15
  16. evilscotsman
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    evilscotsman Space Cowboy

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    [Jan 3, 2009]
    Its because audi tried to play down the use of the turbo in the a4 and wanted to make a small capacity but torquey engine that pulled like a 2.6 but was badged as a 1.8 to make it appeal to the economy crowd / enviro lot.

    So - no gauge, and a very small, quiet turbo!
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  17. J7USS
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    J7USS Shuddup Foooool!!

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    [Jan 3, 2009]
    Electric Turbo!!!:eyebrows:
    #17
  18. evilscotsman
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    evilscotsman Space Cowboy

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    [Jan 3, 2009]
    if only they worked mate :)
    #18
  19. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jan 3, 2009]
    the thing is you likely wouldnt see any difference on the guage...

    the pressure at the manifold would drop due to the leak, so the ECU would use the N75 to tell the turbo to generate more boost...

    This is often the cause of turbo failure on B5 S4's, theres quite a few awkward pipes on those that split, so the boost leaks, pressure getting to the manifold drops, so the ECU simply requests more boost, untill it gets it. Problem is that because of the leak, the turbo is now spinning a lot faster than it should be, and if it goes unchecked, it dies.

    Docurely: i think the chap meant 12k miles not 120k miles...

    The drop in fuel economy is probably indicative of something being amiss. all the air that flows thru the turbo has been measured by the AFM and the engine will add the fuel accordingly. If some of that air is actually leaking out, the mixture ends up rich, and the economy drops. If its bad it will eventually bring on the engine management light.
    #19
  20. s-line stu
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    s-line stu Member

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    [Jan 5, 2009]
    Been to Custom Code agents Midland VW today for a second opinion and as soon as he drove the car and heard the noise he said definitely the turbo. I am waiting for a cost from them to see if they can beat £800 all in from Stafford Audi.
    Will get another final opinion from a local specialist before I part with that much money.

    Stu
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  21. J7USS
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    J7USS Shuddup Foooool!!

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    [Jan 5, 2009]
    Gosh!!!

    Turbo gone already, what a Bummer mate
    Has it been serviced at all??
    #21
  22. bubstar
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    bubstar Member

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    [Jan 5, 2009]
    That's a shame. How long have you had the car and has it been mapped?

    Do you let the turbo cool and wind down before switching off?

    Hope you get it sorted ok :thumbsup:
    #22
  23. s-line stu
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    s-line stu Member

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    [Jan 5, 2009]
    In answer to J7USS and Bubstar I've had the car a year and it had 23K on when I bought it with a full service history and I had it serviced at Stafford Audi not that long ago.

    I had a stage 1 Custom Code map around March last year but I don't drive it hard and I do let the turbo wind down most of the time.

    I guess it's just bad luck as I've had mapped Golfs with 100K on the clock that were fine. The guy at Midland VW did say that this particular engine can be more prone to it (although it's still pretty rare) as the oil feed to the turbo is on the small side and if they replace the turbo they upgrade this at the same time.

    I'll post the outcome once I've got some more quotes.
    #23
  24. bubstar
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    bubstar Member

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    [Jan 5, 2009]
    I guess you can never know how the numpty who owned it before treated it.

    I'm sure it's just a bit of bad luck and you'll get years of trouble free use from the new turbo.
    #24
  25. docurley
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    docurley Moderator Staff Member Moderator

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    [Jan 5, 2009]
    look up Siena he gets good trade prices on Audi parts.
    #25
  26. s-line stu
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    s-line stu Member

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    [Jan 15, 2009]
    Got a price from Birmingham Audi - they said they'd match Stafford Audi at £800 incl. vat.

    A local mechanic that comes highly recommended has said he can supply and fit for £640 incl. vat and that it could be a metal washer in the turbo that sometimes fail and if it is he can fix it and put the turbo back on saving me the cost of a replacement, but obviously he won't know until he takes the turbo off.

    It's booked in for tuesday so I'll see what happens!
    #26
  27. s-line stu
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    s-line stu Member

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    [Jan 25, 2009]
    Finally got it fixed. It did need a new turbo so I went with a local garage who fitted one for £640 inc vat. They said that the old turbo had been overboosting which is why it had failed (maybe due to the remap but I'd have thought that unlikely as it's only a custom code phase one lifting it from 190 to around 225bhp and I don't drive it particularly hard).

    Anyway I've been advised to take it easy for the first 200 miles until it all beds in then it should be back to normal.

    Just out of interest does anyone know if the turbo is different on a 190 than a 150/163 as I thought it was the same but with an additional intercooler?

    Stu
    #27
  28. bubstar
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    bubstar Member

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    [Jan 26, 2009]
    Different turbo and injectors. The 190 isn't just a factory remap!
    #28

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