HELP Sludge - PeachParts Mercedes-Benz Forum

jaybro · #1 04-04-2008, 11:12 AM

HELP! I changed the oil in my 1999 C-280 today, pumping it out of the pan, put in a new filter after adding 7 quarts of Mobile 1 0W-40. Then buttoned it up. I then checked the level with the dip-stick and removed the oil fill cap to add half a quart. What a shock, sludge all over the cap and down into the valve cover. I have never had a car that showed this. I have used Mobile 1 since buying the car new. It is just shy of 20,000 miles. I thought synthetic oil prevented sludge from forming. When I pumped out the old oil there was no sign of sludge. The previous oil change I had done at my indy, did he use regular oil and not synthetic???
HELP what should I do now, is this common? Should I ignore it?
Thanks for your help in advance. jaybro

HuskyMan · #2 04-04-2008, 12:26 PM

as far as I am aware, no FULL (not a "para" or "combined with petroleum") synthetic oil will generate sludge of any type. some oil vendors are now offering "para synthetic" type oils that combine synthetic with dyno oil. sorta like mixing oil with water, why would you want to try and "combine" the two? as to your issue, the sludge might be left over from a prior "dyno" oil change or, as you say, someone slipped some petro oil into the mix when you weren't looking. In an attempt to clear the sludge, some people resort to engine flushing machines. IMHO, this isn't the way to go......a slow and gradual change to synthetic normally clears up the sludge over 2 - 4 oil changes. change early and change often.......also a really GOOD bypass filter (www.oilguard.com) doesn't hurt a thing.......

just for the record, ALL jet aircraft use synthetic oil. this is due to higher operating temperatures and maintenance issues. A mechanic for the U.S. Army once explained to me that the Army NEVER changes the synthetic oil on $750,000 jet turbine engines on the Apache helicopter. his statement gives new meaning to the term "long drain intervals".

lkchris · #3 04-04-2008, 01:25 PM

If the sludge was white or light brown, it's the very common mixture of moisture condensation and motor oil and nothing to worry about. Of course if the moisture is instead coolant, you have a problem.

jlomon · #4 04-04-2008, 01:39 PM

From what I understand it is a common problem with M112 engines due to poor crankcase ventilation with the design. I get this condition with our E320 in colder months, but as soon as the weather gets warm the sludge in the oil cap disappears immediately. There is never any sludge on the dipstick or in the oil when it is drained out.

Johnhef · #5 04-04-2008, 08:52 PM

Goo on the oil cap is pretty common..... but if you only put 7 quarts in you're 1.4 quarts too low.... 8.4 Quarts for a Oil and filter change or 8.0L if you measure things that way.

Also use 5w-40 Mobil-1 now, MB changed the reccommended oil type.

jaybro · #6 04-05-2008, 10:49 AM

On the 1999 C-280 the book does say 8.5 quartz and that may be true with a brand new dry engine,but if I put in 8 qts. I am over the max on my dip stick, with 7.5 qts I am midway between min. and max. on the dip stick.
On the 1999 SL500 the above applies and I put in 8 qts and got a dash board warning that I was over max and had to pump out a quart.

stevebfl · #7 04-05-2008, 11:10 AM

Nearly ten year old motor with less than 20k miles. The first problem is that it isn't driven enough.

The second problem probably is that the oil isn't changed enough. I'll wager the car doesn't even reach oil operating temp ever.

The reason engines sludge in later models is a weird combination of issues. The manufacturers designed service intervals so long that people were having to place oil into the engines between changes. People don't like that. So manufacturers decreased the scavanging effect (reduced flow) of crankcase ventilation systems. Most of the oil used in a modern engine is breathed into the combustion process through crank case vapors.

By reducing vapor flow they reduced oil consumption and they seriously increased the residaul effect of water vapors condensed and harsh combustion gases blow by the rings. These gasses turn water and oil into acids. in a robust pcv system these products would be scavanged properly, but for systems designed for wimpy consummers they created a problem. That problem is exaserbated by long (time based) service intervals and driving conditions that involve short trips where the oil doesn't reach operating temp.

My wife and I live less than a mile from work. My 2004 545 BMW has had 9000 miles put on it in the 2.3 years I have owned it. I change the oil every 6 months which means about every 3-4000 miles. I also drive around an extended block on cooler days to atleast get the cooling system to operating temp.

Johnhef · #8 04-05-2008, 11:01 PM

Quote:

Originally Posted by jaybro

On the 1999 C-280 the book does say 8.5 quartz and that may be true with a brand new dry engine,but if I put in 8 qts. I am over the max on my dip stick, with 7.5 qts I am midway between min. and max. on the dip stick.
On the 1999 SL500 the above applies and I put in 8 qts and got a dash board warning that I was over max and had to pump out a quart.

If thats true then your sucker isn't getting it all out. ~9.5Q is the full amount on a dry engine.

Do you get the engine nice and hot, remove the filter and let the oil in the filter housing drain back to the pan before removing the oil?

The only M112 engine I put 7.9qts into is the 2.6 version. Everything else gets about 8.5, otherwise I'd have a lot of unhappy people with low oil lights on.