Hi All,

I am making a list for my friend's W204 C200 M271 EVO ( turbo ) of 2010..... to renew plastic and hose where it carry potential loss of coolant and also oil or mixing of oil and coolant.
The car is today 14 years old and 93,000KM. 93,000KM in Jakarta Indonesia is equal to approx 93.000KM divided by average 22KM/H = 4,227 heat soaked hours.
I am M276 3.0 Turbo familiar, but not for M271 EVO.


I know 3 major weakness, as per common report and youtube.
1st is coolant loss and/or coolant mixing with oil. Oil cooler + filter housing combo.
2nd is coolant loss from a plastic pipe of HVAC heater core to engine.
3rd one is the oil o-ring of turbocharger oil pipe into engine block..simple o-ring. Leaking of oil.


01. COOLANT MIXING WITH OIL - Oil cooler + filter housing combo. Stupid plastic assy if on M271 EVO.



and the coolant hose for it and the dumb azz plastic coolant pipe









02. COOLANT LOSS - Item #330, the famous plastic coolant pipe. DONE , replaced already.
Weakness is its mounting location hahaah, so pipe got broken by it.




.


All I list above shi-ety plastic + rubber hose will be replaced too.



03. - COOLANT MIXING WITH OIL - Coolant pump output to engine block via timing cover meaning it will cross into timing chain oil bath area
This is what I need to know, anyone ever replaced this seal/o-ring before ? Item #20.
This is cheapo parts, but the amount of work to do it is a NIGHTMARE , same crying pain as my M276.820





Everything timing chain thingy must be removed.

This #20 o-ring is between engine block to timing cover. Timing cover seen from its rear , or from engine block towards water pump or radiator





Timing cover seen from the front





.
04 - COOLANT - Engine block output, to thermostat
I plan to advice to replace this o-ring too, Item #50. This is easy job.




.







and many other rubber hoses..............
and turbo o-ring for oil and coolant
and others..............


I am only so very pissed with that o-ring #20 at timing cover/engine block..
The required tear down of other components to simply access #20 is too much .



Oky doky......


Thanks in advance Guys.

.

 

In your first series of photos - 01 Coolant and Oil Mixing - you will see in your third photo, Item No. 23 being the oil cooler assembly. That interface has a red, unusually shaped "O" ring type seal that fails. Now, assuming that you don't have some other source such as a head gasket problem, that is a likely source of the mixing of coolant and oil. Happens to almost every MB of this era.

 

Yes, well noted, thank you. That is why I will want my friend to change entire oil cooler/filter housing combo and not only item 23 the gasket.
There is another gasket inside the oil filter + cooler combo which MB does not sell. This M271 EVO plastic assy oil cooler/filter housing combo can have its gasket groove distorted, so no new gasket will help.
All cars with oil cooler will suffer this leak at gasket for sure, its a matter of time.

My main concern is this cheap o-ring, but insane amount of work to replace it. Item 20.
Unless one search the EPC well, most owners do not even know such o-ring exist in their M271 EVO ( 1 pc ) M271 older unit uses 2 pcs o-ring there.
M272, M73, M276, M278 will one day leak their equivalent o-ring #20 too and get coolant in engine oil.

I am hoping someone here had experience his o-ring #20 leaking* ( *sorry ) on his M271 EVO and share the info.