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M104, oil in cooling system strange problem....

7K views 11 replies 5 participants last post by  Real1shepherd 
#1 ·
Hello.

Few weeks ago, i found oil in cooling system. OK. Head Gasket.

I removed head, gave to workshop. They resurfaced it, replaced valve seals and checked valves... Everything was OK.

I bought new head gasket (Elring) and head bolts. I assembled everything (bolts was screw accurately, sequence and torque) , everything was ok, engine run accurately.

I cleaned cooling system, but oil still get through cooling system. Liter per 500 km... I also check Oil cooler in oil filter mount and its ok, no leaks.

Any one have a idea ? Broken head ? There's no leaks to outsite of engine or to cylinders, no liquid coolant on oil, no compression leaks to cooling system.... Only oil on liquid coolant...

(sorry for my bad English...)
 
#2 ·
Hello,

How well did you flush everything first? I flushed mine for over an hour and the water was clear and still got a little oil residue after I did the head gasket. I siphoned off whatever showed up in the overflow tank a few times and eventually it cleared. I think the oil gets everywhere in the cooling system and it takes a while to get it all out.
You could try doing a detergent type of flush (prestone Super Flush comes to mind) to remove any possible remaining oil residue and then see if you still are getting oil in the coolant. Good Luck.
 
#12 ·
It's what MB recommends as a service procedure for flushing out the cooling system, after the head has been repaired. So...you're saying in the 10-15 minute flush interval using a MB approved product for this exact purpose,
significant base metals will be cannibalized? If a detergent based solution is better for this purpose, wouldn't MB recommend one by part# ?:confused:

Kevin
 
#5 · (Edited)
I flushed (changed water) system 12 times, at an average 1/week. In last two weeks, i stop flushing and i started to removing oil from overflow tank, using syringe. And from now, i have full, 3 liter bottle with oil removed from system... So i don't thing its a "old oil". Problem must be anywhere else.
 
#6 · (Edited)
Perhaps you have a failed gasket between the oil filter housing & engine block? I think there is 1 small water passage that goes through the housing gasket. It could have failed internally, in a similar way the head gaskets fail.

Also, did you use factory replacement head bolts??? Aftermarket headbolts might be slightly longer, and in combination with the skimmed head, may not provide sufficient sealing although I suspect that would cause running conditions (white smoke, etc.)
 
#7 · (Edited)
I checked, new bolts was minimally (maybe 0,5 - 1 mm) short than old bolts - old was minimally strained. But I bought new bolts, because when i screw out, i damaged one bolt and i can't use it again.

I can take photos of old head gasket.




There's two oil "lines" close to water "lines" ? In front of engine, in right site and in rear, in left - very close ? (looking from front of car)

(sorry for bad quality)


And something else, maybe important:
-i didn't overheat engine. Max achieve temperature - 100 C
-50-100 km before i fount oil, i had a ignition coil failure. Engine worked at 6 cylinders, but often misfired. I must drove ~10 km with this problem. Maybe that is reason ?
 
#8 · (Edited)
#4 piston looks worryingly rusted. It looks like it has been sucking coolant and not fuel for a very long time. Did the coil for #4 piston fail or was it a different one??? These coils are consumables, but failure is usually caused by something else such as the famous biodegradable engine wiring harness.

Why was the whole motor removed to do the headgasket???
 
#10 · (Edited)
Still #4 piston looks unusually clean compared to the others. Need more info re. the coil issue. Are you using new coils (All 3) & new coil-2-plug wires w/ Bosch Super plugs???

Are you still running on the original engine wiring? If so, doing the headgasket probably was too much for the harness. A bad harness can shortcircuit the ECU, which is much more expensive than the harness. Don't let it happen.
 
#11 ·
I replaced one, damaged coil, and all spark plugs. Coil-2-plug wires are ok. After i replace coil, engine started running perfectly.
Engine wiring is rebuild - every wire was replaced by new wire. I spend 2 days for that.
Coil failure after i fix engine wires.

Every pistons looked same, this 4 piston maybe looks than only in photo...
 
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