S4 white exhaust smoke only at high revs
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?