I have 2005 Mercedes sprinter 316CDI Engine version MQ6(115KW/EURO) Motor home, now with 10k miles on.
About 10 months ago, and 5k miles I noticed Blue smoke would emit from the side exhaust on a cold start and idling, and this would be highlighted with a blip of the throttle, this would continue a good while until the engine was hot, but if I drove the Van of a couple of minutes (under load) and idle the Blue smoke would of stopped?
The MB Garage first diagnosed this a possible running in oil being too thin, and passing the rings/valves, so I had a oil change with slightly thicker oil, the problem still continued, then I was told that this is because the engine is still bedding in, and the oil is being left on the cylinder walls when the engine is shut down, and eventually the rings will bed in, and oil will no longer be noticeable on start up!!
Having compared my problem with other similar mileage sprinter 316CDI 2.7L owners, I quickly realised that I was experiencing a complete new problem that clearly was not a characteristic of this engine, or engine running in?
Recently the MB carried out some tests, and no fault codes were reported on the system!!
Injector test, and a test of compression using the Diagnosis Assistance System, the reading I was given for the test of compression is a measurement of 210 1/min, for each of the 5 cylinders, what is this measurement? as MB cannot tell me? And is this a good reading on such a new engine? can this result be converted to the more popular psi, or Bar? What is a good reading in Bar/psi for this engine?
The MB dealer did notice limited play in the Turbo bearing, so based on my history of a litre of oil being burnt and not used approx every 2k miles, and the van smelling like an old bus on tick over, coupled with an emission smoke test result being 0.53 m-1 (twice as high as it would be expected to be on a new engine) max limit being 1.50 so well within.
Decided to replace the Turbo under warranty, but the dreaded Blue some still continues, and now even more noticeable in colder weather.
Now the MB dealer is say there is nothing else they can do as the engine is within MB specification, and MB will not pay them for further more in-depth checks, and the problem is down to the motor home only being used now and then, and that the engine should not be left to idle?
They have conveniently ruled out valve stem seals, as the engine is to new??? But advice I have points to these? How do you check these, and at what cost?
What is causing this problem?
Blue smoke when cold!! Please help? 
Linear Mode
