2006 C4 Hatch Hdi 1.6 Blue Puff of Smoke on Start Up

[boristhespie]

Hi. The other half has a C4 hdi from 2006 which bellows out a big puff of blue smoke on start. But only on start. I remember something on WD saying what this is but just wanting to run it past you experts.

She does get a coolant low warning so was worrying about head gasket but the coolant remains same level so think it is a faulty sensor.

Anyway any ideas?

Also, is K Seal a good idea?

[moizeau]

Blue is oil. When you say 'on start', is that every start, hot or cold, or just when the cars been standing overnight for example? Could be a sticky scraper ring when cold or a weeping valve stem seal, possibly turbo but I'm not really very knowledgeable about those. I'm sure you'll get more advice and thoughts.
How many miles has it done?

[boristhespie]

I think it is just in the morning. She only drives two legs of the same journey. I don't recall is smoking, or at least being as evident later in the day.

It's done about 130,000 ish (I think).