Hello all,

As a newbie I would not want to come with a question but I have a picture that I believe many forum members will find it interesting. My car 2005 C240 has 63000 km on it. I use Mobile 1 0W40 European formula. Last week I was checking oil condition and I saw yellowish sludge-like on oil filler cap. When engine was hot I do not see this sludge. Could any body tell me if it is normal?

All your comments would be greatly appreciated.

Thank you

 

1. Your engine is producing butter
2. How often do you change oil?
3. Have you checked the level IE Is it overfull & foaming the oil?
4. Never seen that color sludge before, normally means head gasket leak.

 

Mine looks like that but about 95% less and only after a few days of short trips.
Have you been driving around town a lot recently?

 

Thank you for replies.

I agree it looks like pure butter. I bought this car last year and did one oil change after I drove about 5000km. It was 46000km when I bought. When the engine is hot looks normal no butter. Is it possible that the prior owner used butter instead of Mobile 1?

 

normal

 

That indicates the car is not being driven enough to evaporate moisture from the engine - typically resulting from short trips.

Once in a while, drive the car at high RPMs (that is, driving in lower gear) like 5K RPM for 10 minutes. That will go away. On other cars, that condensation can effect (incorrect readings) the oil level sensor.

 

This!

Also check the rubber seal on the underside of oil cap, sometimes moisture can get in that way as well.

 

.

 

I'd taste it, just to be sure.

 

Tommy, how do you want OP to mail it to you?

 

In the oil industry we call it Mayonnaise. Low temperature sludge. If your car does low stop/start mileage then please stick to the one year drain interval with approved oil.

 

I'm going to go check mine now. My commute is only 15KM away from home but it's 90% highway driving at 120KPH so the engine is revving at around 2600 and the engine temperature hits just above the 80 mark.

BTW what oil/filter are you using? I'm using Motul 8100 XCESS 5W40 and a Mann filter and was told to avoid buying Mobil 1 as it isn't fully synthetic.

 

There's nothing wrong with the proper weight of Mobil 1. That's what most of us use.

 

Thank you for all contribution. My commute is about 10-15KM from home to work, work to home weekdays. But, Mercedes keeps surprize me. I have been used many other cars (old/new) and never seen something like that. I wasn't driving other cars for hours. I will use Castrol 0W 40 this time to see if it will make any change.

Any other consideration? I do not want to go stealership for this issue. But, I started worriying about it. Could it realy be head gasket??

But, as I said before when the engine get hot I do not see that mayo.

 

If it bothers you send a sample off to Blackstone or similar company for analysis. Also make sure the Castrol is 229.5 approved.

 

Is your engine temperature normal after 10 minutes of service ie around 90'C.

Your thermostat may have failed open which would not allow the engine to evap. the moisture?

If everything is normal ie no head gasket leak or water ingress I would change the oil every 6 months to help prolong your engine life. Only old steam engines prefer emulsified oil on their working surfaces !.

JC

 

Non of the products are technically fully synthetic. Nomenclature varies on what respective countries allow to be termed fully synthetic. Mobil 1 Euro formulation 0W-40 is a fine product. Mobil ! and many of the products today use Group 3 base stocks. What matters is passing Benz HTHS (high temperature, high shear) specs which is very base oil dependent.

 

The Mayonnaise/emulsion shown in the OP's picture is somewhat excessive & could be a leak, crap oil, operating condition related. Whether we like it or not the combustion process produces water.

As Trey says to put your mind at rest either have an oil sample analysed or get hold of a test kit to look for combustion by-products in your coolant.

Cars that operate perpetual 10 & 20 Km trips from a cold start with no hot running in between to evapourate the water off can very quickly get up to 7 or 8% water in the sump. This is why Benz mandates a 1 year oil change limit for low annual milers.

 

Now, I'm no MB mechanic, but shouldn't the first step have been to do an oil/filter change and see if the situation is then resolved? At least it would start to eliminate possible culprits. Then send the old oil for analysis, if that's what you want, but it would at least get the ball rolling.

And provide a lovely spread for toast with jam, of course.

 

If it was my car, first thing I would do is run the engine at high RPM for 10 minutes (NOT running the engine in idle; drive the car on highway staying in lower gear). Most of that will burn off. Condensation is more pronounced during winter months.

Another way to deal with it, as already suggested by others, is to change oil.

 

Its fine.

do a search for "mayo" on the 210 board, you'll see tons of people with the same initial shock and concern, and ultimately showing it to be fine.

My guess, a somewhat crappy pcv system combined with the location and material of the oil fillter tube results in some junk under the oil cap.

nothing to worry about it if it goes away when hot, you're not losing coolant, and you regularly take short trips.

 

Actually, that hadn't been suggested already, which is why I said it.

 

Tommy, I was referring to your suggestion of changing the oil. I should've been explicit in saying 'as Tommy suggested'... :-)

 

Ahhh, much better.

 

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