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S4 white exhaust smoke only at high revs

sun and kath Jun 18, 2007

  1. sun and kath

    sun and kath Member

    my 1999 s4 emits white smoke at high revs - say 4500+.
    If i drive easy, no smoke and no notoiceable water loss - fine for weeks and weeks. If i drive hard i get the white smoke at highrevs and over time the water drops.

    My investigation so far consists of undoing the throttle body and sealling it with plastic sheet and refitting. Then I disconnected the air intake at the maf and with tubing and a funnel blew into the intake to pressurise it. First the crankcase took the pressure , i found a slight leak at the gasket at the back of the cam- which i sealed. So i then took off the crankcase vent form the air intake and sealled that escape. Then when pressuring the air intake, i could hear water bubbling deep down somewhere on the drivers side.

    My suspiction is that the water cooloing the the drivers side turbo is leaking into the turbo/ exhaust when under pressure.

    Any tips or futhther tests i can do ?
    Boost seems okay (by a vagcom test). Car still goes okay. Car still sounds okay - you only notice if you look in the rear mirror if you thrash it.
    Can any gaskets be replaced or is the turbo on the way out?
  2. Blue_Thunder

    Blue_Thunder Well-Known Member

    Have you checked your oil levels? If they drop, I suspect it may be one of the rocker cover gaskets going. This happened to mine.
  3. sun and kath

    sun and kath Member

    Yes it does slowly loose oil. I had not checked against driving hard.

    How does a leaking rocker gasket lead to the exhaust smoke?

    I'll look at these tommorrow
  4. satans child

    satans child project...satans child

    dont worrie about minimal oil loss
    if you drive them as there ment to be driven (pretty hard) they all use a bit of oil
    ive had this arguement with many people and i assure you that they all do it
    ive driven s4's for9 years now and all mine have and my best mates does...:icon_thumright:
  5. jcb

    jcb Active Member

    white smoke is not oil, mine "steams" a little on caneing it, worse on cold days obviously, nto sure if turbo can leak water into the exhaust housing.

    may be onto a new water injection there if it does.....
  6. That god for that. Mine is burning a gallon a week!!

    Only joking, but it does use a fair amount between services, which i kep topped up.

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