Recently I bought 535d LCI kit from eco-tune scotland and beleive me my car is "electric" now. On maxitune immense power at my disposal and I have to be careful where I am doing it. 360+ bhp, 720Nm torque

Now the problem I am seeing is *not* due to eco-tune kit, but only made apparent by taking the dpf off. So I installed dpf off pipe from eco-tune package and started the car up (no tuning done yet) and revved it a bit, I could hear turbo whistle which was good but upon revving high there was blueish smoke, not too much but before it was none so new for the car. Now I know taking the dpf off will introduce smoke in the back but I was expecting black smoke not blue which indicates, incomplete combustion, means oil burning.

Just to let you know some history, I had diesel chiptuning box installed before for an year or so which was also good but I took it off before going ecotune way. While taking it off I noticed some (minor) oil leak around two areas, first near small turbo oil line and next to the breather where it joins the other pipe. See pic below:



My mechanic says it could be injectors, any idea, advise? I want to do preventive maintenance before catastrophic failure.

Note: Car has done 46k miles and no problem in driving whatsoever.

 

I have been told by somemore more knowledgeable then me that Motul oil will be better on tuned engine as high performance engine oil will generate more heat and normal recommended oil isn't designed keeping that extra heat in mind.

Given it is time for oil change now I want to change it with Motul 300v 0w-40 but I see many people replace Mobil 1 0w-40 with Motul 5w-40! Why so?

Motul product range is extremely confusing, can someone please help me understand and suggest me what can I use on my engine. I don't care about LL04 as I don't have dpf.

 

I would be very surprised if changing oil brands would stop your smoking issue. I use Mobil 1 0W-40 and wouldn't think of changing. Call me a victim of advertising, but I can't see Motul being any better.

I would start by replacing the crankcase breather, but really, these cars always seem to get some oil in the intake, be it from the crankcase breather of weeping from the turbo seals.

My car (same engine) gets some black smoke/soot when I boot it, but no blue oil smoke despite there being oil present in the intake pipe. It has had a new crankcase breather and rebuilt small turbo recently, but is also pre-LCI so my cat is still in place whereas yours won't have one.

 

How about this theory:

Mobil 0w-40 is not a racing oil so it will produce more vapour as engine produces more heat then normal specification (350+ degrees) or shall I say it will easily be going way over its boiling point resulting in more steaming. That rising steam will be captured by the breather and will be feeding that steam back into turbo intake, then cooling it off making it oil by intercooler and back in to combustion. As more vapour rises more engine oil will be burning.

Now if we use Motul racing oil something like 300v or 8100 series they normally exceed all the specification of standard oil and 300v is much better at racing and it won't produce that high steam at high engine temperatures hence reducing oil burning.

 

The oil collected by the breather and deposited in the intake isn't due to overheating or vaporizing of the oil in the crankcase. Using an oil with a higher smoking point won't make any difference. Even if we stick with that theory, the temp in the crankcase wouldn't get hot enough to do that to the Mobil 1 or I dare say any quality oil currently on the market.

The vortex style crankcase breather on these engines just doesn't do as good a job of filtering oil droplets from the crankcase vent so you will always get some oil making it's way to the intake. The older style with the replaceable foam filter element did, but that was prone to clogging and causing much bigger issues.

Another option is to add an external oil catch can and feed the crankcase breather to/through that rather than directly to the intake. This is something I have thought of doing myself, just to keep the intake clean/er.

Having said that, if switching to Motul is what you want to do, go for it, the only thing you have to lose is the difference in purchase price (if any) between the two oils.