blue smoke puff on cold start

Hi, my father C70 has completed 40,000. The car was last started 3 days ago. Upon starting it up from cold today, the exhaust emitted a puff of blue smoke. This is not unlike the oil puff which high mileage 340s do!! Im surprised it did this given the low mileage. The car is a T reg so 1999 and has a 2.5 non turbo engine (N series engine). Im thinking that a stem seal is leaking when the car is standing, the oil soon burns off as the engine starts. Ive read that PCV or flametrap clogging can cause blue smoke whilst driving but this fault is on initial cold start up. given the mileage and the fact it is driven gently (even when warm!) I dont think it could be piston rings. also, they wouldnt seal so fast. Is this a common fault? it is something that needs addressing? The car recently had a volvo 40k service including coolant change and brake fluid change. I can check with them if they serviced the flame trap etc but volvo this was deleted prior to model year 1999? look forward to hearing from you Shimon

Hi Shimon, I know absolutely nothing about this particular car/engine, however, the description does sound like a leaky valve stem oil seal. I wouldn't worry about it unless it gets worse. All the best,

Check your breather system, make sure the flame trap has been removed (volvo recall). Also, what oil was used on the service as some of the thinner oils like mobil 1 can cause smoking.