• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Oil in coolant - om602 engine

Dikfrik

G-Wagen Club SA
Joined
Oct 10, 2008
Messages
725
Likes
36
Location
Empangeni, Zululand
#1
Gents

I checked my coolant level earlier this week and discovered a bit of coolant loss - then checking the level tonight to my dismay the cooling water was all black and oily! I checked the engine and gearbox dipstick and oil level is fine and oil still black in engine and red in gearbox with no sign of water (not milky) but the vehicle was standing for a few hours - not sure if that will allow all the water to seperate out of the oil? So hopefully no water mixing with oil but reverse? Apart from the oil cooler where could other sources of oil contaminating cooling water be without getting into the sump. The oil in the cooling water is black so perhaps not the gearbox cooler in the radiator leaking or could it be?

What is my steps in sorting this before next weekend?
 

Andrew

G-Wagen Club SA
Joined
Oct 8, 2008
Messages
3,557
Likes
413
Location
Brits
#2
I thought yours had the gearbox cooler removed from the bottom of the rad? So it is surely not transmission oil?
Isnt engine oil pressure higher than coolant pressure? If so I would guess the engine is injecting oil into the water system. Maybe Pierre will tell you what that heat exchanger behind the injector pump looks like inside.

I had a big perkins diesel many years ago that also put black oil into the radiator from a corroded water-over-oil heat exchanger.
It was also in Empangeni come to think of it. There might be something in the water.....
 

Dikfrik

G-Wagen Club SA
Joined
Oct 10, 2008
Messages
725
Likes
36
Location
Empangeni, Zululand
#3
Thanks Andrew - The transmission oil cooler in the rad is still there and the new cooler is in addition to that. Oil is pitch black so quite certain it is the engine. Some people say..it could be the cylinder head which I certainly hope it is not. The oil cooler sit directly on the filter housing..busy stripping to get to the cooler
I managed to get the last one in SA.. on its way from Cape Town hope to be here on Wednesday and then fit and flush - hope to leave for Theo's farm Friday - need to finish this year on a good note wit good mates..
PS the only problem with Empangeni's water is the fact that you have not tasted it in quite a while..
 

Rolf Redecker

G-Wagen Club SA
Joined
Jan 8, 2009
Messages
565
Likes
98
Location
Windhoek Namibia
#4
[QUOTE="
Isnt engine oil pressure higher than coolant pressure? If so I would guess the engine is injecting oil into the water system. Maybe Pierre will tell you what that heat exchanger behind the injector pump looks like inside......[/QUOTE]
While the engine is running your oil pressure is higher than the cooling water pressure. The moment you switch the engine off, the oil pressure vanishes and the radiator pressure continues to be high, even rises shortly after switching off due to engine heat dissipating into the water without effective circulation and cooling. (I believe the 290 might have a electric circulation pump?)
At the moment the leak between the circuits is so minute that the 5bar oil pressure suffices to push through, while the water leaks back in very small quantities, so that it evaporates and you cannot see it in the oil.
Have it tested at a radiator place.
 

Dikfrik

G-Wagen Club SA
Joined
Oct 10, 2008
Messages
725
Likes
36
Location
Empangeni, Zululand
#5
I agree Rolf - Although i do not see any signs of water in oil i will change it anyway - new cooler is coming tomorrow - I just hope it is the culprit and not the head. It is difficult to find fittings to close off the outlets (all pushfit) to pressure test but i have filled the oil part with boiling water and it seems that some water finds it way to the other side..
 

Dikfrik

G-Wagen Club SA
Joined
Oct 10, 2008
Messages
725
Likes
36
Location
Empangeni, Zululand
#7
Excited to hear about the solution
OK feedback time - first thing for me in 2020 that did not go pear shaped - it was the oil cooler only and the repair was successfully done by replacing with a new unit - it is quite a job -not so much replacing the cooler but flushing the system! We tried to show the leak on the old unit but could not - because all the fittings are push fit sealing with o rings one cannot pressurize it without making special fittings. Filled it up with boiling water to simulate the hot element to see if water leaks through to the other side and also paraffin heating the water side with a hot air gun (blowing hot air through) could not show a significant leak.

The flushing was done with a concoction of water, automatic dishwasher powder, vinegar and lemon juice - especially the lemon juice quickly removed the oil sitting on the top of the radiator element ..This recipe was recommended by the mechanic assisting me who used it successfully on several sprinters he worked on previously
 

Antony

G-Wagen Club SA
Joined
Nov 17, 2008
Messages
926
Likes
104
Location
Johannesburg
#9
Nice to hear you’ve sorted the problem without too much hassle.

May you have many uneventful kilometres in 2021


Sent from my iPhone using Tapatalk