Hey folks. My 1998 E320 got a nice bath and once-over this weekend. While checking out the engine and related components for a few minutes, I discovered that the underside of my oil filler cap was covered in a milky white substance. I had seen this before but never in this large of a quantity. It was thick and looked like someone had dipped my oil cap in a Starbucks Mocha Frappuchino complete with cream colored streaks. I wiped it off as best as I could and even mopped up a bit that was in the oil filler neck. My dipstick was perfect and the oil was a nice golden color and right at the mark. The oil has about 6K on it. I plan on a change at 7K.

I checked out the coolant level to see if the unthinkable (coolant in the oil) was happening... it was completely full as it has been since the summer.

What gives? I do mostly normal and quite calm driving as this is my daily driver. Do I need to hammer it more to get this stuff out of here? Any comments would be welcome. I have read some other threads that say it is common for this to occur due to moisture. I thought that moisture in the crankcase was a bad thing?! Thanks in advance!
Scuddog

 

in those engines.The condensate from the oil pan rises and coagulates with the oil and forms the common peanut butter coffee gunk.Just wipe it off.No worries,no needing to check for combustion gases in the coolant.Just take some longer trips and let the moisture evaporate.
Now if you did an oil change and all the oil you sucked out looked like that,then you could worry.
No need to change oil at 7k mobil1 0w40 syn mb spec is good well up to and beyond the FSS 10k miles.Use a fleece filter.www.autohausaz.com has them for about $11.

 

POPPED A HEAD GASKET OR JUST MOISTURE ANY MILKY LOOKING OIL ON DIP STICK? IS IT SMOKING WHITE SMOKE OUT OF EXHAUST? CHANGE OUT THE OIL WITH SOME FRESH OIL GOOD LUCK.

 

Is all the oil milky white too? If so then its a blown head gasket or the aluminum head is corroded and you have a leak. Will be expensive to repair as the bolts holding the head on often sheer when they being taken out.

If the oil is not milky, then its just gunk, wipe it off, and drive on.

Hopefully its the second possibility!!

 

Thanks gents for the great response. I did wipe off the crap and will check it again this weekend. The oil on the dipstick (and what wipes off of the dipstick) is still that nice golden brown color. It isn't even favoring black. I do not detect any signs that this gunk is showing up in the oil and I do check it every time I gas up. (sometime every second fill up).

I'll continue to monitor the oil cap and the dipstick every time I gas up. If I even detect for a moment that the oil on the stick looks remotely like what I was seeing... I will change it right away and call my indie mechanic.

It's hard to believe that something could be wrong... it fires right up... gets super gas mileage... pulls strong...has received pampered maintenance and PM maintenance...idles like it's new.... does not smoke at all unless I am really pushing the rpms when jumping on it. The smoke that does come out is faintly black... like fuel exhaust not white like coolant or oil smoke. It's hardly noticeable at all. Someone told me that since it has been 55K since my last tune up that it could be a simple adjustment which would be dialed in with a tune up. Anyway...I digress...

My ride is due for a balance and rotate in about 1K miles. Is there something that my MB certified indie mechanic can check to see if it is indeed an issue with the head gasket? Should he check the exhaust etc... as stated below? I can also just ask him about that gunk.

Thanks gents.

 

fine.Why do you need a mechanic?You can do your own oil changes,spark plugs,filters.All easy jobs.
177k miles did you get your high mile plaque from Mercedes as an award.
you should apply.it goes on the grill.
ohlord

 

OhLord,
I do my own oil changes and some of the other fluids as well. I didn't do the plugs last time but may do them this time if the DIY threads show where the plugs clearly are. That will be in about 10K miles anyway.

I'm only looking for advice from mechanics and others that have encountered this coffee like gunk on the underside of the oil cap. So far, I have received a great deal of good info.

My thought process now is that I have a thermostat that is stuck in the open position. My car takes a long time to heat up and the temp gauge takes about 10 minutes in the AM to get near the middle of the operating range. I know that these devices fail in the open position. Perhaps the moisture in my motor is not being evaporated quickly enough during my normal driving due to the fact that my motor doesn't get "hot" enough to do the job? So... how long should it take for my motor to get right up to operating temp? Maybe this doesn't even matter at all anyway.

I do have the 250K km badge proudly displayed on the grille. It was applied when I rolled over 155K miles as required by MB. My old 240 had the 250K and 500K km badges on it before I sold it... at a nice profit!

I'll keep checking the oil and cap during fillups, then I will take the car in for a bal/rotate in about 1K miles. At that point I will chat with my mechanic and see what his own car does. (He owns a 99 E320 with over 200K on the clock) I hope it's nothing more than moisture which will go away as the temp rises this spring. I'd hate to have to sink money into this fine motor.

 

will evap that moisture,go for a nice long drive.It will be fine.Maintained M112 engines have no head gasket problems.You don't worry.Plugs are easy if you get the 17mm boot removal tool pm me I have them and supply the diy.NGK 7090 plugs 12 of them are only about 36 bucks.Do not use multi tip plugs and do not use anti seize on the threads.