Howdy oil experts,
I have a 2012 Sprinter 2500 with the OM642 3.0L V6 diesel. It's got approx 140,000km on it. I had the emissions system including EGR deleted about 40k ago. About 30k ago I filled it with Amsoil Signature Series Max-Duty Synthetic Diesel Oil 0W-40. This is apparently the best that Amsoil has to offer for light duty diesels like the OM642.
A few thousand km later, I started noticing a puff of blue smoke coming out the exhaust when starting the engine while hot and the engine would run rough for a few seconds or until I stepped on it to raise the RPM up a little. Around this time, I also noticed that when cold starting the engine (vehicle parked in 70 F ambient temperature), I could hear the familiar "clack-clack" of an unhappy valve or two. The sound disappeared within 1 second and the engine ran normally. That has not changed a bit. Over the last 20,000km, I've not noticed any change (condition is not worsening). I am going to be doing an oil change shortly and I am wondering if this oil may be the wrong oil for this engine. Is it possible that the high levels of zinc in this oil could be causing problems for the close-tolerance hydraulic lifters that the OM642 uses?
I've also thought that maybe the 0W rating of this oil is just too thin (that does not explain the aforementioned problem with hot startup), but I don't want to use an oil with a higher winter viscosity. Last winter I noticed that when cold starting the engine in below-freezing temperatures, the "clack-clack" unhappy valve noise went on for as long as 2-3 seconds. I installed an oil pan heater to keep the oil thinner during the winter and that helped reduce the duration of valve noise at startup, so I know that in it's current condition, this engine doesn't like thick oil at startup. I've also heard about loose/sloppy timing chains and tensioner problems with this engine model, but this is definitely valve noise, not a timing chain (I know what that sounds like on the OM642).
SO... I am looking for a suggestion for my next oil change. I'd like to stick with Amsoil, but I am wondering if i should go to an oil with a higher W (winter) viscosity or maybe an oil with less zinc additives.
The engine seems to be wearing nicely so far. I had the oil tested a few thousand km ago and TBN is good at 5 and wear metals are low, although the bypass filter system may be filtering out some wear metals. It consumed about 1 quart of oil over 20,000km.
You can see the oil test result from a few thousand KM ago here:https://www.bobistheoilguy.com/foru...sprinter-amsoil-0w-40-18k-km#Post5088967