Se7enUp Posted November 30, 2009 Share Posted November 30, 2009 My new 300tdi has started smoking - but only at startup and after prolonged periods of idling. The smoke is whiteish with a grey/blue tinge. At (cold) start up, I get the normal puff of grey smoke but this is followed by a light stream of grey/blue smoke that stops after around 30 seconds of driving. If I get stuck in a traffic jam, the smoking starts again and continues till I get out of the jam, then it stops. When driving normally, I can't see any smoke, even at niight with car headlights behind me. Coolant level is constant with no "pulsing" seen in the expansion tank. Oil level has dropped a little, maybe 1.5mm on the dipstick in the last 200 miles. Can anyone take a guess as to the most likely cause for the smoke. My guess is shot valve stem oil seals or maybe a knackered turbo oil seal???? Any help pin pointing the cause would be appreciated as I'm hoping to try and get it sorted before the christmas break. Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted November 30, 2009 Share Posted November 30, 2009 apart from what you've said, check tappet clearances, I recently saw a dealer mantained 300tdi that had 3 of the tappets set so tightly that there was no clearance at all Quote Link to comment Share on other sites More sharing options...
Se7enUp Posted November 30, 2009 Author Share Posted November 30, 2009 On a sort of connected note..... Can anyone tell me how work valve stem oil seals can make an engine smoke at idle/low revs. I understand how they can cause smoke at start up but can't get my head round the smoking at idle part. I guess my lack of mechanical knowledge is shining through Quote Link to comment Share on other sites More sharing options...
markyboy Posted November 30, 2009 Share Posted November 30, 2009 On a sort of connected note..... Can anyone tell me how work valve stem oil seals can make an engine smoke at idle/low revs. I understand how they can cause smoke at start up but can't get my head round the smoking at idle part. I guess my lack of mechanical knowledge is shining through Valve stem seals normally cause smoking on start up, during gear changes/on overrun (when very worn), and during prolonged periods of engine idling/slow running. They also leak oil during normal/fast engine running but it is not noticeable because the engine is running quickly and the oil is burnt and dispersed quickly enough for it not to be noticeable. HTH Mark. Quote Link to comment Share on other sites More sharing options...
Se7enUp Posted November 30, 2009 Author Share Posted November 30, 2009 Thanks Mark - that helps a lot. I guess the smoke (at idle) is due to the cooler temperature in the combustion chamber. As a way of ruling out the Turbo.... If the seals in the turbo were failing and causing the smoke, can anyone tell me where I should look for tell tale oil in the inlet system and also - how much oil is normal / abnormal? Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted November 30, 2009 Share Posted November 30, 2009 Look for oil, lots of it, not just a dribble, inside the turbo compressor housing, inlet manifold and intercooler etc. If you find enough that it's running out then it could well be turbo. Normally though if enough oil is leaking past then the engine runs on it's own oil and is unstoppable. How many miles has the vehicle done? and does it have a snorkel? Quote Link to comment Share on other sites More sharing options...
disco_al Posted November 30, 2009 Share Posted November 30, 2009 sounds like the turbo outlet seals on the way out. check the joins in your exhaust system, you may find oil leaking from them. if not then split one of the joins and see how oily it is. Quote Link to comment Share on other sites More sharing options...
Se7enUp Posted November 30, 2009 Author Share Posted November 30, 2009 Well, this weekend I swapped out the starter and as part of this, removed the pipe from the airbox to the turbo. This has a very light coating of "dry" oil. nothing was sopping wet. I also removed the centre box on the exhaust and this was bone dry, albeit sooty and black. the motor has only done 90k miles and runs very well, apart from the intermittant smoke. The smoke is not what you'd call severe, it's just something I'd like to get sorted out before it gets ... severe. Quote Link to comment Share on other sites More sharing options...
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