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I've tried doing research on my own about this topic but haven't been able to find anything definitive, just some people's best guesses. To be brief, I want to know if anyone else has the additional cooling measures (Code 139 on their data card) for the oil cooling? The first picture below is of a standard M278 without the additional cooling, the second pic is of my engine with the 139 cooling code, and the last is the M157 from an AMG. It appears as though the M278s with the additional oil cooling has the same setup as the M157, but I've never seen another M278 with this in place on YouTube, vehicle sale listings, or technical documentation. I have Xentry and no technical documents show this setup on an M278. Anybody else have this on their M278?
To be specific, the differences are the two additional oil lines coming into the top of the filter housing to the left of the oil filter cap. The AMG pic, the last one, has them in a red box.
Standard M278 My M278 AMG/M157
Last edited by Phillip Bagshaw; Aug 20, 2025 at 08:55 PM.
You're the only other person I've seen that has them! Have you ran your VIN through a VIN decoder to get a vehicle data card? I ran mine through https://www.lastvin.com and have the code 139. I'm curious about the benefits this might have compared to the cars without it.
You're the only other person I've seen that has them! Have you ran your VIN through a VIN decoder to get a vehicle data card? I ran mine through https://www.lastvin.com and have the code 139. I'm curious about the benefits this might have compared to the cars without it.
I have run the VIN and have the data card, I DON'T have that code.
That is so wrong! I couldn't edit it either to fix my wrong info. I've had my car now 3 weeks and been reading a bunch and got a lot of good info from a Mercedes Master Tech. I found out this is the cooling from the M157 from a revised update for more oil flow pressure and cooling the engine also to aid in the cylinder wall scoring issue. I found this out while doing a oil change. The oil filter I bought had a stem on the bottom what K&N said was the right one. The filter in my car was just a cartridge filter no stem this filter had Hengist AMG Mercedes and part # on the bottom. The oil housing cap with the 27mm hex design also has Hengsit on it too. The later M278s have this I was told and that's what those added lines are for the added oil flow. I'm glad we have this on our M278s.
Wow, I have no idea how I'm seeing this over a year later, but that's great info to have! I have a 2012, I'm surprised that that is in place on such an early variant of the M278. Did your master tech happen to say when that started to appear on them? I've only ever seen this present on the M157s, even really good 3rd-party performance shops like VRP have stated that my engine doesn't have the same cooling measures, so it doesn't sound super common?
Again, thank you for that info - really appreciate it. Next time I'm in there I'll have to get my borescope out and see if I have any considerable scoring at 110k miles.
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