[neilryan54]

hi , can anyone tell me why blue smoke comes out of my exhaust when the car first starts in the morning but is fine all day.? cheers

[CO335D]

Taken from a fellow diesel site I used to frequent:

Blue smoke is often evident at cold start, which can reflect reduced oil control due to carbon fouling deposits around the piston rings and/or cylinder glaze.

[Yozh]

I thought a small puff at start-up was normal.

[neilryan54]

thanks for your help. neil

[glitdi]

A little blue can signify a few things...
1) bad glow plug...
2) Improper burn of diesel from lack of heat.Typically car ecu will dial back fuel and advance timing to limit this. Less prominent in modern diesels.
3) Or low compression, excessive blow by.
Most likely 1 or2
Possibly a weak plug, don't know if it works or not it was a nice trick on the older diesels.
Cycle the key a couple of times before starting, warming up the cylinder and the plug. In our cars I guess that means pushing the start button without the brake engaged a few times.
Another thought try a different source of diesel or get some additives such as howes diesel conditioner... Bmw states no additives, however Howes is cheap abundant, you can pick up def for cheap when you are at the truck stop and howes is not alcohol based (important when adding additives) also def, dpf,scr friendly.

[Xtremektm]

Ok blue smoke is lubrication oil burning problem. if you recent change the oil can be an incorrect grade of lubricating oil OR.... the bad news.... worn or damaged valve steam, guide, work or sticking piston ring or worn cylinder bores. Just make sure is blue and not black or grey smoke ( almost a bad fuel burning for a restrictions in the air supply ( filter), leaking injector and more...