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1998 S4 - have i blown the turbos?

Discussion in 'A4/S4 forum(B5 Chassis)' started by calvin, Jul 2, 2008.

  1. calvin
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    calvin parked up

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    Help!

    I have a (well it was great!) S4 twin-turbo that has just covered 83000 miles (i've had it since 42k and turbos were replaced under wty at around 15k for some reason). Its been mildly remapped by MRC Tuning (great guys!) nearly 2 years ago (60k) and has run really well since.

    Just had it MOT'd today and did that foolish thing of thinking I must sell her really (reluctantly!) and, then, on an enthusiastic take off tonight, heard a slight "pop", which coincided with power loss, noticed a small puff of smoke out the back and that was that, NO TURBO - or at least, no boost.

    The car drove ok after that, though clearly not as swiftly as it had (!) and I stopped shortly and checked - all running fine at idle, then noticed a slight mechanical rattle like a loose baffle or heatshield (comes and goes depending on throttle). I drove the car gently home and checked it over and the sound is coming from the back of the engine, down around the downpipes, but I cant exactly find where or what..!

    Have I popped the turbos or (PLEASE!) have I popped something simple like a diverter valve or summat - has anyone else had the same and what do i do next?!

    btw - there's no evidence of rough running or any smoke at all on driving.
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  2. jcb
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    jcb Active Member

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    check for a boost leak, turbos don;t tend to pop when they go, more likely to be a hose.
    #2
  3. calvin
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    calvin parked up

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    thanks - ok, thats on the list for tomorrow - what about the clatter though - that wasnt there before..
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  4. hiltoa
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    hiltoa VAG erfahren

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    With any luck the clatter is just the jubilee clip on the popped hose touching the exhaust... Gotta think positively! If it is a goosed turbo, at least it gives you the perfect excuse to uprate those puny K03s... :)
    #4
  5. docurley
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    docurley Moderator Staff Member Moderator

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    If your turbo let go you can be sure there would be white smoke so I would think like the others you popped a pipe.
    #5
  6. andybnwc
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    andybnwc Member

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    also for the noise check the heatshield around the downpipe
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  7. Andy.B
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    Andy.B Member

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    If you have popped a hose off you should be able to hear a rush of air coming from the pipe thats off when your driving. But for both turbos to go at the same time is very unlikely or very unlucky.
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  8. Fraser
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    Fraser Member

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    hopefully just boost leak and some of the older hoses going or as other have said a jubilee clip - fingers crossed for you

    if it is hoses might be time to get them all replaced for piece of mind
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  9. Siena
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    Siena Active Member

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    Turbos don't always smoke when they die.
    The can fail in various ways:

    1) Oil seal failure - white / blue smoke
    2) Bearing failure - loud whistling, even at part throttle
    3) Turbine shaft failure - generally noisy / metallic / rattling
    4) Turbine blade damage / failure - poor performance, little / no boost

    Just replaced BOTH turbos on a 2007 BMW 535D. Luckily, it didn't require an engine pull.

    The turbine shafts had both failed, and the turbine blades had rubbed against the housings, destroying them.

    But get your pipework checked for leaks, turbos will overwork / over spin as they have to work twice as hard to make boost, if there are leaks.
    #9
  10. calvin
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    calvin parked up

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    Ok, started the car up tonight with the intention of checking for boost leaks, but was fairly quickly greeted with white smoke from the exhaust, so looks like turbo failure. The metallic clatter must be a shaft rattling or bits of vanes (!!!?) but engine seems happy - turned it off and closed the garage door!

    Plan now is to pull the engine and get the turbos overhauled and replaced, or look at K04 upgrade, but to be honest I was going to sell the car,so I think the stock (and least expensive?) route is how i shall go unless someone can convince me otherwise.

    Are there any posts to aid with engine pull? Do I need worry about the quattro setup for example?

    Thanks for all your crossed fingers - shame, but there you go.:shrug:
    #10
  11. Siena
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    Siena Active Member

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    No issue with quattro drivetrain after an engine pull, but if you decide to unbolt the subframe, you'll need front wheel alignment.

    Good luck!
    #11
  12. calvin
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    calvin parked up

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    Hi all, thanks for the feedback.

    Has anyone else done this job that can give me a summary or any pointers of things I need to know / avoid?

    Is is deffo that I have to pull the engine, or is there any way I can get the turbos out without?

    What are my options in terms of replacing the turbo(s) with matched replacements? Who should / shouldnt I use for this service?
    Is there anything else I should do whilst its out (if it is!)

    I'm no stranger to getting into the oily bits, but never on my S4..

    Any help and advice really appreciated.

    Cheers!
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  13. dummi
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    dummi smoking a6

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    you need to take the engine out to get to the turbo's, engine and gearbox come out quite easily together
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  14. Siena
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    Siena Active Member

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    You can remove engine and transmission together, or just the engine on its own.

    Less work to pull the engine solo, especially if you don't have access to a hoist.
    If you pull both, you'll have to lower the subframe, which means front wheel geometry will have to be reset.

    You're also creating more work, when there's no need to. Disconnecting driveshafts, propshaft, linkage, removing clutch slave etc.
    #14
  15. Siena
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    Siena Active Member

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    Calvin, where abouts in the country are you?
    #15
  16. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Reading your fault description i'd be wary of just swapping out the turbos. Check all the pipework carefully for splits, as i suspect you have blown a boost hose, and the leak that caused the turbos to overspeed and thats wrecked the bearings.

    Turbo internals dont normally make a pop noise, which is why i think that was caused by blowing out a boost hose somewhere especially as it was immediately followed by a loss of power.

    How much white smoke were you getting from the exhaust?
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  17. calvin
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    calvin parked up

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    Thanks all, for the feedback.

    Ok, in order:
    Am in Sussex.

    Will check pipes etc, but when I said "pop" it was a figure of speech. I was executing a good, hoof-down launch and got heaps of boost (it would have been at about peak boost as we set off), accellerated off for a second or so, then there was a bit of a pop, a puff of smoke (it was dark) and no boost. Then I noticed the faint clatter from the exhaust. I have to say that your idea (Aragorn) of a burst hose that's caused the turbo to overspin sounds quite plausible. I'd had no issues up to now with the turbos.

    There was a puff of smoke initially, and the engine was warm. I drove it gently home and still no smoke.

    Left it overnight and started it up again - and a reasonable amount of white smoke and intermittent clatter (like a hoseclip rattling) from one side of the exhaust (Drivers)

    Turned it off and shut the door at this point!

    From feedback so far, I think my plan is (please add suggestions):
    > engine only out
    > check all hoses and pipes (replace as necessary)
    > check turbos and get both refurbished (somewhere, tbc)
    > put all back together again.
    #17
  18. bahnstorm.net
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    bahnstorm.net Member

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    pressure test it first to see if any pipes are duff,i would be inclined to remove the downpipe and check the turbo before removing engine,just to be sure
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  19. Blue_Thunder
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    Blue_Thunder Active Member

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    Also try removing your lower intercooler pipes. If a turbo has gone, chances are the respective intercooler will be filled with oil, this is quite likely if you are getting quite a bit of white smoke.

    Sounds very like when one of my turbos blew to be honest though.
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  20. calvin
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    calvin parked up

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    Ok, 4 hours or so in and we've got the front off, rad out, pipes off and done a lot of scratching of heads to work out how to get to all the bellhousing bolts and exhaust manifold studs / nuts...!

    Oh, and disconnected about a gazillion wires and seem to have a garage full of bits but the engine bay looks just as full!

    The intercoolers do have a little oil in the pipes, so will have to drain / clean those out if i can but no evidence yet of hose splits..

    will keep you posted - are planning on only pulling engine, so if anyone has further hints or tips - all welcomed!
    #20
  21. Siena
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    Siena Active Member

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    I usually leave the wiring harness on the engine.

    Just disconnect the harness within the electronic box / ECU point.
    #21
  22. calvin
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    calvin parked up

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    cheers Sienna - might do that then, and put back all the connectors !!

    but how do you get to the bellhousing bolts? I can barely see em, let alone reach them and as yet havent sussed the exhaust bolts either as they are hidden by the guards.

    sorry for the dumb q's - the car is now in a workshop half a mile away (lots of space) so i cant work on it every day..
    #22
  23. bahnstorm.net
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    bahnstorm.net Member

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    lower the front subframe,remove engine and box,leave downpipes connected and split them at the centre sections,much easier removing engine and box,as sienna said leave loom attatched and remove the plugs from the fuse box and ecu...
    #23
  24. calvin
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    calvin parked up

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    Hi all, Thanks for advice. got the engine out 2 weeks ago and sent off the turbos - one has completely failed - the shaft broken and turbine wrecked. The other looks fine and has little play.

    Having spoken to the refurbers, they are concerned as to how it failed, claiming it could be oul shortage - I do know that on this occasion (probably one of very few ever) the engine only had about a minute of warming up and the oil would not have been hot - would that be enough to kill the turbo, or so i look for something more sinister, like a oil feed problem, blockage, or split in the hoses? I've not seen any splits, but any clues as to what to look for would be really appreciated!

    thanks in advance - if anyone is in sussex and wants to have a shufty at the pile of bits that my S4 now is, you're welcome!
    #24
  25. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    i would replace the oil feed lines from the block to the turbo as they can get blocked up.

    replace the dump valves while its apart too for peace of mind
    #25
  26. Dan Gliballs
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    Dan Gliballs Active Member

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    Which end of Sussex are you in chap?

    I'm Horsham way.
    #26
  27. Blue_Thunder
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    Blue_Thunder Active Member

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    Would second that about the oil lines. Also worth doing the water lines whilst you are there.

    Definately fit some facelift exhaust manifolds(or RS4 ones) as the pre-facelift ones are prone to failure. You're not wanting to need to pull the engine again (or have shards of manifold lining shooting through your new turbos!). Perhaps also worth looking at changing the clutch whilst it's out.

    Wouldn't bother with the DV's unless they've failed. Obviously you can change these with the engine in-situ, so it's not too much of an issue.

    Are you just getting your K03's refurbed? Not tempted to see the episode as an opportunity to fit some lovely K04's?
    :rock:

    As for the lack of oil issue, overspinning of the turbos caused by boost leaks can sometimes be mistaken for this. Did you check all the usual suspects, ie: F-hose, TBB, DV's, etc?

    Make sure you check and double check all of your hoses before refitting the engine. The first engine pull I had needed to be redone because one of the pipes on the turbos hadn't been fitted... luckily at the garage's expense.

    And finally, MAKE SURE YOUR OIL GETS UP TO TEMPERATURE (60-70) BEFORE BOOTING IT!!!
    #27
  28. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    why do you think i suggested to change the dump valves? they're £20 each so he may as well do them when its all out as if they've not been changed recently they're not going to be in the best of health anyway
    #28
  29. aposegil
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    aposegil Member

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    hello calvin

    sorry to hear about the turbo failure even thou k03 common to fail especially after remap due to even the smallest boost leak means turbos are over spooling.

    wish been on here earlier as the easiest way to get the engien out is

    front panel off

    disconnect front drive shafts and prop aliong with gear linkage

    disconnect wiring loom from under the ecu

    then just aircon pipes and power steering pipes and should all come out nice and easy about 4 hour job

    whilst its out depending on funds most def do oil lines to feed and return they can get crappy over years

    after that I higly recomend going K04 route or atleast get some rs4 manifolds on there.

    def do intercoolers again RS4 ones help keep those intake temps done and then after that coudl upgrade the Y feed pipe to the APR Bi pipe and replace our vacumm hoses especially the F hoses (most common to go on a s4 and cause turbo failue)

    and for future invest in one of these bad boys

    http://cgi.ebay.co.uk/AUDI-S4-RS4-T...18&_trksid=p3286.c0.m14&timeout=1218791179023

    not the most professional kit out there but helps me and a very good mate find those annoying boost leaks and could save you a few pennies in the future.

    good luck with it all

    ps im in lewes east sussex if you need any advice and in north london :)
    #29
  30. Blue_Thunder
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    Blue_Thunder Active Member

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    The 2 Divertor Valves sit on top of the engine right at the front of the engine bay in an S4, so they can be replaced very easily (5-10 mins) if need be when the engine is in place.

    You made it sound as though it was something which should be done whilst the engine was out.
    #30
  31. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    while i wasnt aware of their exact location on an S4 (1.8t is buried in a bit more), i was more suggesting they should be replaced as a matter of course along with testing all the hoses for leaks etc.
    #31
  32. aposegil
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    aposegil Member

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    if you do replace them go for the 710N items. They are the later style ones more reliable can hold higher boost levels.

    06A 145 710 N part number but yes again original s4 ones leak over time meaning another boost leak. easy to do about 20-30min job
    #32
  33. Fraser
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    Fraser Member

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    change the hosing to the DV's as well, they will have likely perished over time and should be replaced with silicon ones
    #33

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