229.51 vs 229.52?

[thorsen]

I own a 2014 ML350 BlueTec. I'm really confused if I need to use 229.52 or if I can use 229.51
The cost difference between the two is about $30-$40 per oil change.

I wasn't aware of the sludging issue with these engines until after I bought it but have been diligent about changing the oil with 229.52 every 3k miles in the winter (it's cold in Chicago) and 5k miles in the summer. I found a gas station that sells diesel with less than 5% biodiesel so I'm good there (these engines don't like biodiesel).

I CarMax'ed it and bought the extended warranty to 125k miles. Current miles are around 65k. I'm willing to take the car to at least 125k miles (as long as I keep the warranty intact!) but I want to make sure I use the right oil - hence my confusion over 229.51 vs 229.52.

Mercedes says these can use 229.51 OR 229.52:

OM 642 - up to and including modification year 2016
except: OM 642 EU6 in BR 164.124/.824, BR 251.124, BR 221 (UK), BR 222 (UK)
OM 642 in BR 463.306/.336/.346
OM 642 Bin5 in BR 164.125/.825, BR 251.125 (only USA and Canada)
OM 642 EU4 in BR 221.122 (UK)

Those in the Except: bucket must use 229.52

My ML is a 166.024 with engine 642.826. I'm having trouble understanding Bin5, BR, etc.
Can anyone help me decode this and see if I need 229.51 or 229.52?

[Graham]

Can't help with the emission designations.

However it seems Mobil 1 comes either as ESP 5W30 or ESP X1 0W30 and both of these meet both 229.51 and 229.52 specs. Should be available on-line or elsewhere for $9/qt or less?
I saw Mercedes oil on Amazon for $52.50/6pack which is also about $9/qt.
https://www.amazon.com/Mercedes-Benz-5W30-Synthetic-229-52/dp/B00R0CRISI

My 2014 GLK250 called for 229.51, but now dealer uses 229.52. Both have same low ash content. Don't know what else is different.

[ROLLGUY]

I read this article: sludging issue shortly after I got my 07 E320 Bluetec. I am not sure if I can be of any help, but I have been running Mobil 1 ESP (not sure if it is .51 or .52) oil in it, and changing at 5K intervals. The article focuses on the Sprinter, which can be considered more "severe duty" than a sedan or your ML. I believe your ML definitely needs the ESP oil because of it having the AdBlue system. My '07 does not, but I am running ESP oil anyway. Again, probably not much help, but that is my experience.

[thorsen]

I dug out the owner's manual and 229.51 is specified. So it's technically OK to use it, but...
I thought I could save serious money using 229.51 over 229.52. I usually buy the Mercedes-branded oil you linked to but I thought the Total Oil would save me some coin. The difference between an oil change with 229.51 and 229.52 is about $12, or $50 a year. If I was saving >$25 an oil change it might be worth it, but for $12 I'll just buy the newest spec.

For what it's worth, this chart shows 229.51 vs 229.52. The big change is for fuel economy.