Is the exhaust emissions affected by using cheap diesel instead of premium diesel? Resent purchase, got blue smoke that would fail an MOT, garage has carried out every test that indicates the engine is fine and it runs fine but still blue smoke?? Idea's anyone.

hi

Blue smoke is usually burning engine oil, not diesel, excess diesel burning is black smoke

sounds more like bad valve seals or turbo seals if its a tdi

if its turbo, checking the pipe work between turbo and engine will tell you, will be full of oil and so will intercooler

very unlikely its valve stem seal, they tend to smoke on first start up and on over run

cheers

Joe

Hi John

Joe is quite right. Blue = Oil, Black = Soot.

You say it is a recent purchase, in which case I would be going back to the seller if they are a dealer. When you say the Garage has carried out "every test" have they done as Joe suggests and looked for oil in the air intake system. Have you checked engine oil level is not over-filled?

Regards

John