Same engine, different cars, different OCI in owner's manual, why?

[OM605]

I had three cars with the same engine (M111) and i really wonder why they all have way different service intervals in their manuals. They all call for 229.1 oil.

- 1995 Mercedes W124 E200 : normal : 10 000 kms, severe : 5 000 kms.
- 1998 Mercedes W210 E200 : normal : 20 000 kms, severe : 10 000 kms.
- 1998 Mercedes W202 C180 : no mention of normal/severe, 15 000 kms. (worth mentioning, had a 95 W202 C200 diesel with the 15 000 kms interval too.)

 

[Gene K]

1995 to 1998 sounds like normal increase as standard service intervals have increased.This is common for many manufacturers.

10,000/20,000 vs 15,000 looks like a simplification to avoid depending on an owner to choose the correct interval. Manuals for different models are often not updated at the same time.

If I owned it my inclination would be to follow the 15,000 km with M-B 229.1 but I have often chosen service intervals between the severe and normal OCI (5000 mi on a vehicle that called for 3750 or 7500 on conventional oil)

 

[JT20]

Sounds similar to the situation on Volkswagen engine. Same engine (?) different car different OCI recommendations even oil grade recommendations.

Some would debate if it is the same engine. Similar to how Nissan, 1989 and 1990 was a KA24E SOHC engine and 1991 and later was a KA24DE DOHC engine. Or some other possible internal difference. I'm not sure a difference like that small enough to not make a whole new engine designation necessary (i.e. bump in displacement, EJ22 to EJ25 or Nissan VQ 3.5 to 3.7L) would be significant enough to change OCI ?

But this question is about the Mercedes engine.

 

[OilUzer]

That's why I never pay attention to owner's manual and go by color*, touch and smell ... If it's getting too dark, it's out. Don't run very brown* or black* oil.

* Note:
Experts may disagree but it's your car.

Edit:
Another reason I will never use dark-colored oils (e.g. RP) no matter how great they are!

 

[RamFan]

That's why I never pay attention to owner's manual and go by color*, touch and smell ... If it's getting too dark, it's out. Don't run very brown* or black* oil.

Yeah, it’s not like the various highly educated engineers that are part of a vehicle’s development have the knowledge appropriate to develop maintenance schedules. /s

 

[OilUzer]

Yeah, it’s not like the various highly educated engineers that are part of a vehicle’s development have the knowledge appropriate to develop maintenance schedules. /s

lol
And I would like to see you reduce your oci in your signature DI and Turbo engines. j/k

 

[JT20]

Yeah, it’s not like the various highly educated engineers that are part of a vehicle’s development have the knowledge appropriate to develop maintenance schedules. /s

If they sometimes put the wrong numbers on the cap

 

[OM605]

1995 to 1998 sounds like normal increase as standard service intervals have increased.This is common for many manufacturers.

10,000/20,000 vs 15,000 looks like a simplification to avoid depending on an owner to choose the correct interval. Manuals for different models are often not updated at the same time.

If I owned it my inclination would be to follow the 15,000 km with M-B 229.1 but I have often chosen service intervals between the severe and normal OCI (5000 mi on a vehicle that called for 3750 or 7500 on conventional oil)

What's interesting is the fact they went from normal/severe to a single 15k recommendation with the W202 in 1993 and back to the normal/severe with the W210 in about 1995.

 

[Gimpy1]

It may be the same engine but it may have a different tune in the ecm, which changes everything from power to transmission settings etc. It could also be that while it may be the same engine, the OEM could have upgraded some internal parts or due to warranty issues or unforseen problems may have changed the maitenence schedule. And finally it could be where the vehicle was built if it was built in Germany, US or any other country they may change the maitenence schedule depending on the region the vehicle may be sold in. I see this alot with VW.

 

[Silver]

Or could have different piston rings, bearing specs, etc. Basically they call the engine the same thing, that's all that can be assumed. Also, part of he extension is probably marketing. "Oh, BMW extended their service interval! We have to!"

 

[OM605]

Something else i wonder is that oil grade recommandations are all over the place for these cars. The chart shown in the manual shows everything from 0w30 up to 20w50 and 10w60. I thought that things like clearances are what they are, some car's manuals and oil caps tell you tu use only one grade.

 

[ZeeOSix]

Something else i wonder is that oil grade recommandations are all over the place for these cars. The chart shown in the manual shows everything from 0w30 up to 20w50 and 10w60. I thought that things like clearances are what they are, some car's manuals and oil caps tell you tu use only one grade.

Engine bearing clearances have basocally been the same for decades, so the misconception that certain cars need certain viscoity oil because of "clearances" is a fallacy. The fact that the same exact engine in other parts of the world showing a whole spectrum of acceptable oil viscosity proves that clearances don't drive what oil viscosity is recommended. In the USA it's CAFE that drives what viscosity the manufactures specify.

 

[OM605]

Thanks for the clarification, i've come to the conclusion that i'll be fine with any viscosity as long as it is 229.1/3/5 with a minimum 3.5 HTHS. 0/5w20 or a low HTHS 5w30 i wouldn't try. Maybe with a spec as high as 229.5, the choice regarding viscosity only comes down to personnal preference, if the engine burns oil, the type of trips or engine noise.

 

[Kamele0N]

Are all 3 M111 engines with the same kW/L output? Bigger fuel consumption lowers TBN reserve in oil (more (sulphur) byproducts)

What was your sulphur content in a fuel in your country in 1995&1998....?

One M111 registered under EURO1 vs other as EURO2?

 

[OM605]

The sulphur content could be one explanation as well as the better syn oils being used. It could be why the W124s had a 10k normal / 5k severe interval.

I just checked and all early W210s (1995-1997) have the same 15k interval as the W202s but they added a 7.5k severe recommendation. Why a severe interval only for the E class and not the C class ? The engines are the exact same.

The explanation for the 20k normal / 10k severe of my former W210 E200 seems to be that they wanted the same interval for all the W210s when they released the M112/3 engines with the fleece filters along with the 229.3 spec (which wasn't even enough since they released 229.5 shortly after ?). I think this is kind of foolish since there's no fleece filter available for the M111 engine.

To me it makes no sense at all, i can't believe engineers who came up with the lifetime fluid idea in the 722.6 transmission of the same cars. This is the whole reason why i am so reluctant about trying a 15k kms OCI, let alone 20k. Maybe perfectly fine with the newer and cleaner M112/3 but with a M111 ? mmh...