My 1999 C280 has started consuming oil. It has just over 118,000 miles and
up until this point never used any oil between changes. It now uses about 1
quart every 500-600 mile when on highway trips only. It doesn't consume oil
during normal daily driving. I can drive it daily for a month of driving
(about 1,000 miles) and it doesn't use any oil but when I take a trip and
drive 4-5 hours at highway speed it uses the oil. What could be causing it
to use oil during the highway driving?
Thanks,
Jim
Take A Guess - 29 Dec 2006 00:40 GMT
Generally, oil consumption increases with power demands on an engine so
this is a symptom --- of something.
If it were my car I'd check the PCV valve to ensure the crankcase
venting system is clear and not allowing pressure to force oil past the
valve guide seals. The valve guide seals would be the next suspect.
Suggest you consider a higher SAE weight oil i.e. 20W - 40 or 20W - 50.
Jim - 29 Dec 2006 01:39 GMT
As far as I can tell it doesn't have a PCV valve. Does anyone know if it
does and where it is located?
Thanks.
> Generally, oil consumption increases with power demands on an engine so
> this is a symptom --- of something.
[quoted text clipped - 4 lines]
>
> Suggest you consider a higher SAE weight oil i.e. 20W - 40 or 20W - 50.
- - 29 Dec 2006 04:00 GMT
> As far as I can tell it doesn't have a PCV valve. Does anyone know if it
> does and where it is located?
Look up your w202 and appropriate engine at the following (go to the cars
link - don't worry about putting in your VIN). You will find lots of
exploded diagrams of all the systems.
http://www.detali.ru/cat/oem_mb.asp
Start at the section 14 for exhaust and intake manifolds.
Doug
Jim - 29 Dec 2006 22:44 GMT
Thanks, the site is just as you indicated. I found 2 crankcase ventilation
hoses but no valve. I'll check the hoses this weekend to see if they may be
plugged.
Jim
>> As far as I can tell it doesn't have a PCV valve. Does anyone know if
>> it does and where it is located?
[quoted text clipped - 8 lines]
>
> Doug
Karl - 29 Dec 2006 02:39 GMT
I will bet that it is using oil in town but fuel is being pushed past the rings and it raises your
oil level. Then you take it out on the highway and the heat evaporates the fuel in the oil and all
of a sudden you believe you are only burning oil on the highway trips.....
Are you using regular oil or synthetic oil?
> My 1999 C280 has started consuming oil. It has just over 118,000 miles and
> up until this point never used any oil between changes. It now uses about 1
[quoted text clipped - 7 lines]
>
> Jim
Take A Guess - 29 Dec 2006 04:48 GMT
Jim - 29 Dec 2006 22:31 GMT
I've used synthetic since the first oil change. I normally make 2-3 hiway
trips a year and everything was fine until a month ago.
>I will bet that it is using oil in town but fuel is being pushed past the
>rings and it raises your
[quoted text clipped - 19 lines]
>>
>> Jim
Roland Franzius - 30 Dec 2006 10:47 GMT
Jim schrieb:
> My 1999 C280 has started consuming oil. It has just over 118,000 miles and
> up until this point never used any oil between changes. It now uses about 1
[quoted text clipped - 3 lines]
> drive 4-5 hours at highway speed it uses the oil. What could be causing it
> to use oil during the highway driving?
The consumption is quite normal at high speed driving especially long
uphills. The valves and the head take maximum temperature and the hot
oil is thickened only by additives. Nevertheless it develops foam and
fog wich is burnt because the intake sucks it.
Try an oil with higher basic viscosity and/or replace the valve seals.
Check compression, low compression may cause head and piston overheating.

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Roland Franzius