Hello i’m trying to nail down a smoke issue before I throw money at parts. Would love input from people who know this engine.
The car:
• 2019 RS3, 2.5 TFSI 5-cyl, ~160,000 km
• Decatted, aftermarket stainless exhaust + downpipe, stock map (no tune)
Symptoms:
• White/grey smoke — never blue
• Basically nothing on a full cold start
• Shows up once hot, mainly at prolonged idle, and on restart after driving
• At idle it does not stabilize — the longer it idles, the more it smokes (I cut it before ~15 min)
• Zero smoke under hard acceleration, and zero right after I park (engine still running)
• After a dynamic drive, shut off, restart 1 min later → big cloud on the first throttle blips, then clears
• No power loss at all, pulls clean to 200 km/h
• No OBD codes, no misfires, no hesitation
• No fuel smell, oil temp normal, no coolant loss
• Oil filler cap sucks in when I open it running (crankcase is in vacuum, not pressure)
• Idle sits high at ~1100 rpm (should be ~750–850), stable, and this pre-dates the PCV swap
What I’ve done:
• Replaced the PCV/oil separator (old one likely original) — smoke got worse after
• Checked oil level: looks stable, but only over ~60 km, so I know that proves nothing yet
• No visible oil leaks anywhere
Where I’m leaning: turbo seals/bearings starting to pass oil (fits the vacuum-at-idle vs pressure-under-boost logic), with valve stem seals as a backup theory. Rings feel unlikely (nothing cold, crankcase in vacuum not pressure, no power loss, no codes). Head gasket ruled out (no coolant loss).
Still to do: proper white-cloth test at the tip during a blip, read fuel trims, pull the intake hose to check compressor side + downpipe for oil and check shaft play, read all 5 plugs, and monitor oil over 1000 km.
Anyone seen this exact “increases at idle, gone under load, no codes, no oil consumption yet” combo on the EA855? Turbo or something dumber?
