15-40 oil in my M112-Good idea? - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 01-30-2021, 03:42 PM

Not wanting to start an "oil war", just want some opinion and/or experience on using 15-40 conventional oil in my M112 ('04 E320). From my research, the main reason for this oil NOT being used (or recommended) from the factory is the added ZDDP can kill catalytic converters (from burning oil). I don't think my M112 burns any oil. Also, thinner oils are used for higher fuel economy. However, I have heard of MANY people running this oil in EVERYTHING!! (old cars, new cars, equipment, gas diesel etc.). I would like to run 15-40 conventional oil in my M112, as I have access to a 55 gallon drum. I do run this oil in all my Diesels anyway, but would like to add my gasser to the mix, and don't want any engine failures because of my choice of oil. I like to go no more than 5,000 miles between changes (multiples of 5,000 is also easy to remember for this old brain of mine). So, what say you?????

Duke2.6 · #2 01-30-2021, 05:43 PM

Theoretically the typically higher concentration of P in CK-4 oils will "age" catalysts faster than the lower concentration in S-category oils, but "your mileage may vary".

I don't see a huge liability for you here, and it may be worth the convenience and cost savings of using bulk C-category oil. I recommend C-category for all cars with sliding surface valve train components like my '88 190E 2.6... don't know if your M112 is "roller everything", but that's what current S-category oils with lower concentrations of anti-wear additives are meant for.

Some CK-4 oils have much less than the 1200 PPM allowable P concentration because ZDDP has been reduced due to the advent of newer Boron based anti-wear additives. I don't know if Boron is an issue with catalysts, and maybe the jury is still out on the subject.

If you can find a spec sheet for the brand C-category oil check it out. I recall that Delo has reduced P, but they don't list a Boron concentration. The important thing to know is that all C-category oils have to pass the tougher than S-category wear test, and this can be done more than one way. Up to 1200 PPM P from ZDDP or less ZDDP supplemented with a new Boron-based additive both get the job done.

Assuming your E320 is performing well in emission testing and you're not driving it into the ground it may be exempt from emission testing due to age before the catalyst goes tango uniform or a major repair like a transmission overhaul may consign it to car heaven before the catalyst goes south.

I don't think you're taking a big risk using C-category; 15-40 is okay for consistent cold starts down to 15-20F, and I doubt if a difference in fuel consumption between 15W-40 and 0W-40 could be detected without laboratory equipment.

There's more information in my oil article. I wrote it primarily for the vintage Corvette community, but there's a lot of good FACTUAL information in it that blows up a lot of internet myths (like "they took all the zink out of oil").

https://stlouisncrs.org/news_files/St_Louis_NCRS_Chapter_July_2011.pdf

Duke

ROLLGUY · #3 01-30-2021, 10:19 PM

Duke, thanks for the detailed response. The slight risk of ruining a cat from running 15-40 oil does not bother me in the least. From what I have found, the impact is minimal. My car does not use any oil between changes, so I doubt the cat will be affected in any way. It has passed emissions testing with no problem. It would be nice to find someone that has used this oil in their engine, and would give thumbs up or down. I may have to be my own "guinea pig" for this one.......Rich

ROLLGUY · #4 01-30-2021, 10:37 PM

I just read https://stlouisncrs.org/news_files/St_Louis_NCRS_Chapter_July_2011.pdf
and man is that packed with great info! I also spent some time on the "Bob is the oil guy" forum, and some of the posts read just like the above article. I have pretty much decided to run the 15-40 oil in my car. I have not gotten a look at the label on the barrel, but I will check it out. I am sure it meets all the proper specs, as it is used in all my friend's cars and trucks (mostly Mercedes-Benz Diesels).......Rich

t walgamuth · #5 01-30-2021, 11:09 PM

I tried rotella 15 40 in my 84 500 SEC. It was too thick and caused at least one of my automatic adjusters to collapse and stay collapsed making a noticeable ticking sound. I switched back to whatever the factory said to use and no more trouble.

tjts1 · #6 01-31-2021, 01:19 AM

Quote:

Originally Posted by ROLLGUY

Not wanting to start an "oil war", just want some opinion and/or experience on using 15-40 conventional oil in my M112 ('04 E320). From my research, the main reason for this oil NOT being used (or recommended) from the factory is the added ZDDP can kill catalytic converters (from burning oil). I don't think my M112 burns any oil. Also, thinner oils are used for higher fuel economy. However, I have heard of MANY people running this oil in EVERYTHING!! (old cars, new cars, equipment, gas diesel etc.). I would like to run 15-40 conventional oil in my M112, as I have access to a 55 gallon drum. I do run this oil in all my Diesels anyway, but would like to add my gasser to the mix, and don't want any engine failures because of my choice of oil. I like to go no more than 5,000 miles between changes (multiples of 5,000 is also easy to remember for this old brain of mine). So, what say you?????

I use 0w40 in my 04 E320 and 02 C320 for 10k mile OCI and 15w40 in my diesels, 5k mile OCI. If I had a 55 gallon of 15w40 I would be doing exactly what you're proposing. Assuming you're not in an extremely cold climate the m112 will be just fine on 15w40.

Ferdman · #7 01-31-2021, 08:24 AM

Refer to your Owner's Manual for the proper weight oil for your 2004 E320. Regardless of the weight I suspect it recommends synthetic oil. I run Mobil 1 in our MB vehicles. Saving a few bucks on oil may ending up costing you big bucks in the long run ... for a major engine repair. Is it worth the risk?

ROLLGUY · #8 01-31-2021, 09:37 AM

Quote:

Originally Posted by tjts1

I use 0w40 in my 04 E320 and 02 C320 for 10k mile OCI and 15w40 in my diesels, 5k mile OCI. If I had a 55 gallon of 15w40 I would be doing exactly what you're proposing. Assuming you're not in an extremely cold climate the m112 will be just fine on 15w40.

I have been using synthetic S rated oil in the E320, and the C rated oil in the old Diesels. I have not tried C rated oil in the newer gas engines (mine and a friend's M112), but desire to go with one oil for everything.

Bottom line: I am only looking for actual real world statistics and/or experience that would sway me from running 15-40 C rated oil in my M112.

MB140300SD · #9 01-31-2021, 09:31 PM

I ran a synthetic 15w40 in my 01 for about 25k miles. That car has 252k on it now and it does use some oil, maybe a qt every 2k miles or so. I was worried it was too thick for cold starts and usually about the coldest morning here is teens to 20s. Sometimes it gets colder than that but kind of rare. Most of the time I ran it was probably mid 20's as the lowest, and during summer months. Might have been my imagination but it seemed like I got more lifter tick at cold start. The last oil change I used Castrol 0W40 and it seemed like I do not have the lifter tick for a couple of seconds unless its been sitting for a few days. Once again, might be my imagination and I may try the 15w40 synthetic again. This particular oil is rate CK and SN. With my large fleet of various vehicles I wanted to find one oil to stock.

BTW, from what I recall the temp charts show 15w40 good down to 5 degrees

Duke2.6 · #10 02-03-2021, 12:29 PM

Quote:

Originally Posted by t walgamuth

I tried rotella 15 40 in my 84 500 SEC. It was too thick and caused at least one of my automatic adjusters to collapse and stay collapsed making a noticeable ticking sound. I switched back to whatever the factory said to use and no more trouble.

I seriously doubt if 15W-40 had anything to do with lifter collapse. I had one collapse on my erstwhile '84 190E 2.3 (replaced on warranty) that I sold to buy my '88 190E 2.6.

Most the viscosity range charts I've looked at from various manufacturers indicate that a 15W is okay down to 15-20F CONSISTANT cold starts and occasionally lower. If your cold starts are consistently below 15-20F use the "synthetic" 5W-40 CK-4. Of course it's more expensive than 15W-40 because it uses more "synthetic" base stocks that have a wider viscosity range.

Duke

oldsinner111 · #11 02-03-2021, 12:35 PM

been using it in my M104.994 for 12 years

MB140300SD · #12 02-03-2021, 12:45 PM

What about these synthetic 15w40 oils that are out now? It used to be 15w40 was dino and 5w40 was synthetic, but now there are synthetic 15w40 oils. My assumption is these are more sheer stable than 5w40? Do they flow better cold than dino 15w40 even though they are the same weight?

Duke2.6 · #13 02-04-2021, 11:30 AM

First, understand that there is no generally accepted technical or legal definition of "synthetic".

Typical C-category 15W-40s are not considered "synthetic" but they do require more Group 2 and Group 3 base stocks to meet current oxidation resistance tests. Maybe you can call them "semi-synthetics".

C-category 5W-40s are generally considered "synthetic" because most of the base stock is Groups 2, 3, and 4, which is what it takes to achieve their wide viscosity range.

As a general rule synthetics have greater service life because of their greater resistance to oxidation, but most models where synthetic is recommended have oil quality monitors.

Pick a winter grade viscosity that's okay for cold starts down to the typical low temperatures you expect while the oil is in service, and change it at a frequency that makes reasonable sense based on the manufacturer's recommended service interval, how quickly you accumulate mileage, and whether the oil is conventional or so called synthetic.

Guys seem to get tied up in knots over what kind of oil to use, but it shouldn't be an ordeal if you have good information, but the trouble is that the world (and internet) are full of myths and misinformation about engine oil.

SAE viscosity grades cover a fairly wide range of absolute viscosities. If you want to fret over this look up manufacturer's specs sheets, which usually list pour points and absolute viscosities at both very low and high temperatures. For a given viscosity it doesn't matter if the oil is conventional or "synthetic" they will both flow the same at a specific viscosity.

Duke