Ivanrad

Before i did service b the car asked me for 1 quart of oil. So i performed service b 300 miles earlier than planned. everything went smooth and i noticed my oil cap had a mustard like substance someone told me that happens when coolant mixes with the oil due to a faulty head gasket. So i called up my mechanic he performed a "block test" i think thats how you spell it. And it showed no oil in the coolant. I also observed tiny metal shards in the coolant tank . My mechanic told me it might be radiator leak fixer. I am so down about this i love the c320 please help. see attached picture.

Glyn M Ruck

Mayonnaise under the oil cap is emulsified water/oil. This can be due to a coolant leak into the oil system from a head gasket leak but it can also be from the combustion process as a result of too many short trips with the engine never getting to operating temperature for long enough to evapourate the water. Water content in the sump can get up to 7 or 8% in short cold running.

Try & pull a sample from the sump with a thief pump. Place it on a hot stove plate or in a teaspoon & heat with a cigarette lighter & listen for a crackle like frying chips. This is an indication of water in oil.

What is the typical duty cycle of your car?

Metal shards in the coolant tank are unusual but certainly not a sign of major problem. The worst thing they could be is solder failing in the radiator or the auxilliary coolant pump failing.

contact148

yup mine did that everywinter when i was doing short trips

go for a long drive (45mins or more) then the crap will go away

Ivanrad

did the oil check everything says perfect. my mechanic is going to drain the oil to make sure its not a head gasket.

Carsy

Make sure the engine top end breathing system is open & working. Sometimes a hose can be blocked or kinked to the engine air intake.

TBayinMaine

I have the same problem with my 2000 E-320 minus the metal in coolant. All of the information is great, I will check all of the above and see how it goes. Hope it is one of the above not a head gasket!

6speedclk

The shaving in the coolent could be from a previously failed water pump or your pump could failing. You should check and see if the pully has any play.
The peanut butter is probbly jest from short trip driving. I have never herd of a block, head, or gasket failing on a 112 or 113 engine.

Ivanrad

Okay confirmed no headgasket leak but my waterpump is on its way . Are aftermarket ones safe ? If so which ones ? How long does it take to replace a waterpump.
Also is the waterpump internal or external ?
Update : mechanic gave me an estimate for 470$ with the part ( oem )and labor .

TBayinMaine

Thanks to all adding in. I did clean out the emulsified oil off the oil fill cap. Check all breather hoses and lines ( 20" vac) on all. Changed oil and filter, did reg. maintenance 500 miles later all is good. It does get cold and humid at the same time here in Maine. Must be those short trips! Thank you all!!!!