The brief
The Scirocco had smoke evaporating from the engine bay, disturbing and a bit scary, with the engine feeling flat too. He brought it in straight away, the right call, smoke from the engine wants checking. The culprit was the supercharger charge hose. On this engine the supercharger pumps pressurised air through a run of charge hoses to the intake, and those hoses carry a little oil mist from the crankcase breather along with the boost. The rubber heat-cycles under pressure and a hose splits, so boost leaks out, that's the flat feel, and the oily air that escapes lands on the hot engine and flashes off as a wisp of smoke. A split charge hose doesn't reseal, so it needs replacing.
The diagnosis
Diagnostics confirmed underboost fault codes, and a check found a split in the supercharger charge hose, bleeding boost and letting oily air escape onto hot parts, which is exactly the flat feel and the smoke. The supercharger itself, the intercooler and the rest of the pipework checked out. That's a hose replacement, fresh rubber and a new clamp where the old had split, then the codes cleared.
The work
The split supercharger charge hose was removed along with the worn clamp, and a new genuine VW-spec hose fitted with a new clamp, the other joints in the charge pipework checked while everything was apart. The fault codes were cleared and the engine's boost adaptations reset so it could relearn against a sealed system. A road test confirmed strong, clean boost, no smoke from the engine bay, the flat feel gone, and the light staying off.
The outcome
Strong boost, clean throttle response, no smoke from the engine bay, and no warning light. The Scirocco went home with the charge system sealed and pulling properly again. A split charge hose robs the engine of its boost and the oily air it leaks makes that scary wisp of smoke, so renewing the hose and letting the engine relearn put the running right.
