oil in coolant recovery - PeachParts Mercedes-Benz Forum

JHZR2 · #1 01-15-2003, 04:11 PM

Hi,

Today I was out rebuilding my monovalve, and had out my digital camera, so took a pic of the drops of oil in my recovery bottle.
The drops are never more that what you see in the picture. They look fairly black, so I would have to guess that they are motor oil.
For the last 12K plus miles, the drops have been about the same in quantity. I flushed the system once, and they showed back up a few days and hunderds of miles later, in the same amount. No sign of a pressure leak overboard from the cylinder to the coolant, no coolant in the oil, and just this tiny bit of oil in the coolant. No sign of cooling system efficiency loss, the temp is always great.
Is this something to worry about? Despite probably nearly 20K miles since I first noticed this (no idea how long before that there were drips) there has been no change in the amount of drops oranything like that, and the car runs great.
Is some drips normal? I have read many times that diesel heads all have small cracks in them from the pressure, so maybe some timy bit of oil like this is common? I would like to not have to do a head job on the car, as I dont have the $$$. What are the chances of something minor like this erupting into a major failure without a lot of notice beforehand (like more oil showing up, or some other characteristic of a bad head gasket, etc)?

Any info/comments would be appreciated.
Thanks

JMH

lrg · #2 01-15-2003, 05:41 PM

Sure looks like oil to me (nice photo by the way). It's the later (1987 on) OM603 engines with alloy heads that tend to have problems with cracks in the head. From what I've seen/heard of the earlier cars with iron heads (which includes yours) it takes alot of abuse to damage the head. My guess is it's a head gasket problem which while not common is not unheard of either. My suggestion would be to do a compression test to see if you have an obvious loss of pressure. If not keep driving it as long as you are sure you aren't getting any coolant in the oil and the problem doesn't get worse.

psfred · #3 01-15-2003, 08:33 PM

Probably water pump lubricant. I've seen the same on my 280 SE, just a few tiny spots of dark oil floating in the filler neck, never change.

If you have a bad head gasket or cracked head, you will also get cold pressure in the cooling system, and quite a bit more oil than that!

Peter

Stevo · #4 01-15-2003, 11:45 PM

Peter
I'l bet you just made his day, or evening

YES!

JHZR2 · #5 01-15-2003, 11:49 PM

And How!!!

Pump lubricant sounds good to me

JMH

engatwork · #6 01-16-2003, 06:52 AM

Peter - not sure what "water pump lubricant is". If it is water pump lubricant shouldn't it eventually not show up with enough coolant changes. The only problem I see with it is the detrimental effects to the coolant hoses. Isn't it funny how, prior to having coolant reservoir tanks, no one ever really noticed stuff like this

.

psfred · #7 01-16-2003, 09:36 PM

Jim:

I'm not sure exactly what the stuff is, but it is listed on every container of anti-freeze I've every bought, and MB used to sell it separately -- also heater valve lubricant for the cars with heater valves (W115 and earlier, maybe W123 manual systems too).

Peter

lrg · #8 01-17-2003, 12:46 PM

I don't believe the pump lubricant you are talking about is black and floats around like that in the coolant. As I think about this though I'm not sure my first obversation about a bad head gasket is necessarily right either. I think psfred is right, if you have no pressure in the coolant system after it cools then you probably don't have a leak. More likely, at one time some oil somehow got in the system and has never come out. When you drain it, since the oil stays on the top of the coolant, it will stay behind with the little bit of coolant that you never quite get out. Flushing the system just moves it around so it takes a while before the oil droplets return to the expansion tank. I'd try sucking them out from the expansion tank 2 or 3 times ands see if they continue to come back. It could be that you'll gradually remove them and see fewer each time. If so I doubt you have a head and/or gasket problem. Keep a careful eye out for coolant in your oil for a while anyway, just to be on the safe side. Good luck.