I have recently come across a blue smoke incident with my truck. I started after I did a oil change and went from Rotella T to JD Plus50.

I have occasional blue smoke on slight acceleration after a long or light throttle decel.

Let me try to explain a little more...

When driving around in stop and go traffic with VERY light throttle input I once in a while get about 5-8sec of blue smoke from my stack, then goes away. Might do it twice within a 30mile commute.

Then on the hill to my house its approx 3miles of downhill where I am in decel with foot off, when I get to the flats and roll into it slowly (25mph school zone) I get some blue smoke that goes away after 5-8sec or so.

It wont do it at idle, free-rev or under moderate power....any ideas???

Im thinking that this JD Plus 50 might by too thin and getting by the rings or it has shrank the valve seals...anyone have experience with JD Plus 50???

Im not too worried about it now, but would like to know if it gets worse where to look.

 

Blue smoke is generally caused by excessive engine oil getting into the combustion chamber. The source of the oil is speculation. If it was a gas engine with a throttle plate and a corresponding vacuum in the intake tract, I'd suspect the valve guides but in a diesel I'm not sure that's accurate. Worn or broken rings can cause blue smoke as well. You also sometimes see blue smoke from excessive idling where the engine is cool and you wash the cylinders down --- then when you put some heat in the cylinders by working the engine a bit, the excess fuel and oil that accujlates above the fire ring next to the cylinder walls gets splashed around and burns, but since it's not atomized, it doesn't burn completely, resulting in a bluish smoke. A leaking seal in the turbo can let oil into the cylinders as well. I think I'd try changing back to the oil you were using before and see if you still have the symptom. If the symptoms go away, I think I'd stay with that brand of oil. You also might want to check the intake air piping to see if you have oil going through the aftercooler from the turbo.

 

I'm going to change the oil this week and see what happens, if there is no change then I'll pull the turbo apart and check for bearing wear.

Trucks only got 37k on it, so I don't think it's rings or valve seals, but washdown sounds like a good canadiate. How does one associate washdown with smoke?

 

Checked shaft endplay and I've got 1-1.5 mm play front to back! So I ordered a new cartridge and will be here on Thursday!

Oh well, guess when you buy used parts that were "rebuilt" you just never know