Intermittand smoke from 1.8T

[Snowy9371]

I have a 2001 VW Passat 1.8T 20v with 89k miles.

When driving through heavy traffic (ie, idling etc) and going at slow speeds (ie, in 5th at 30mph meaning about 1200rpm which is just of labouring the engine), I sometimes get a blue/grey smoke from the exhaust (funny that eh?). This only happens after about 20 minutes in these driving conditions and does not happen all the time. It's not dead thick smoke, just looks like the smoke from a badly worn engine (ie, a 2007 Mondeo with 2k miles).

This smoke goes away after about 1/4 mile and I have noticed that it goes away if I either dip my rear-view mirror or get a bit of speed up - it might not happen again for a week or so.

The engine runs fine, idles fine (even when having a smoke) and performs fine. Looking at various sites, it could be turbo oil-seals, oil return pipe or the PCV system - any ideas or advice?

[blocko]

I also have a similar problem with my 1998 1.8T Sport (142k!!!). Engine smooth in all gears and speeds etc, but when started and left to idle for about 4 minutes it bellows out smoke for about a minute then all clear!!??

[Snowy9371]

I have taken a portion of the PCV system off today (the metal pipe portion that runs parallel to the top of the engine then goes into the air intake hose). I noticed quite a bit of oily paste-like gunk in it. I also noticed quite a bit of this gunk in the rubber connecting hoses. I am now almost certain that this is the cause (as the turbo cannot return the oil when the PCV system is blocked which causes the oil to escape through the oil seals in the turbo). There is also a one-way valve connected to the air intake hose as the end of this pipe, so it may be that this is sludged up which may be causing it to stick closed).

I am also thinking that if the end-part of the PCV system is blocked up to this amount, lord knows what the starting portion is like!!

I rang up my local VW Specialist (Volkspeed) and have explained this to him and will be taking it up this Saturday. He explained that also the rubber connecting hoses can becomed weakened over time if they are contaminated with oily sludge and can sometimes collapse to a point where restricted air-flow can occur - not a desirable action on a PCV (ie, part of the breathing system for your engine!!). He stated that this is unlikely to be a turbo problem, but to get it sorted as soon as I can.