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engine oil cooler

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by bignick, Dec 11, 2012.

  1. bignick

    bignick Senior Member

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    dose anyone know if the engine oil cooler on a ml 270 cdi is water cooled iv got oil in my water head is not gone got black oil in header tank :(
     
  2. oigle

    oigle Senior Member

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    As I understand it, the little rad on the front is part of the cooling system and contains water (coolant). This, and the normal engine coolant, run through a heat transfer unit on the front P/S of the engine. Engine oil and auto tranny fluid also travel through this transfer unit and are cooled/heated accordingly. Seems a complicated setup. Would be better to just have engine oil going through that and the auto fluid working through the extra rad at the front.
    To answer your question, corrosion within this transfer unit could cause engine oil and coolant to mix.
     
    Last edited: Dec 11, 2012
  3. S.Speed

    S.Speed Senior Member

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    Oh Great!!
    So not only the VALEO Rad issue but Alloy rot as well to worry about..
    I agree..Some aspects of the engine are too complicated.

    P.S Glad to see you sorted your internet connection with the forum Ian..
     
    Last edited: Dec 12, 2012
  4. whitenemesis

    whitenemesis Senior Member

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    Keep the coolant protection up to strength and there would be no corrosion?

    Life really is too short to worry about ifs and maybes
     
  5. oigle

    oigle Senior Member

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    Yes, back on track, Simon. Still unsure of reason it went silly - computers!!!
     
  6. oigle

    oigle Senior Member

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    That is the point - there are many who don't keep the coolant % where it ought to be and think the stuff lasts forever. I change mine every 2 years whether it needs it or not. I've seen too much damage to heads and other alloy parts over the years from lack of maintenance on this issue. Cheap insurance.
     
  7. whitenemesis

    whitenemesis Senior Member

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    Prevention always better/cheaper than cure ;)
     
  8. EmilysDad

    EmilysDad Senior Member

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    No idea about your side of the world, but over here in Blighty, there's still the perception that the coolant just needs 'antifreeze' & if it isn't cold enough to freeze, then what's in the coolant system will be good enough. The anti-corrosion bit completely escapes them ;)
     
  9. OP
    bignick

    bignick Senior Member

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    So any idea what I need to change ?
     
  10. oigle

    oigle Senior Member

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    Generally speaking, we don't worry about the antifreeze properties too much for obvious reasons. The corrosion factor is what we think about and the antifreeze/antiboil properties are basically a side benefit.
     
  11. oigle

    oigle Senior Member

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    Very hard to say. We could be barking up the wrong tree. It was the only place I could think of where oil and water could mix, other than areas like head gasket or cracked block. I'm not even sure if the heat exchanger is made from alloy or steel. I haven't had one off. Maybe one of our techies could comment there.
    I think I would remove the heat exchanger and have it checked thoroughly for corrosion and holes as a first step. If it is alloy and corroded, then what about the state of the rest of the motor's alloy bits?? Don't want to scare you but ......
     
    Last edited: Dec 12, 2012
  12. EmilysDad

    EmilysDad Senior Member

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    You lucky buggers! :lol: :lol: :lol: :lol:
     
  13. fester

    fester Guest

    Haven't been on here for a while but if you haven't sorted this yet. Yes the oil cooler is definately water cooled. it is mounted on the rear side of the timing case on the passenger side. You can just see it under the manifold.

    The passages are quite small and fine so not sure if it corrodes easier but my Jeep (same engine) has had 3 of them stuff up (1 in my ownership) and as far as I can tell from service records and records from previous owner the coolant was changed as required. The other possible issue could be stray current and maybe it affects the cooler first being so fine. I don't really know except that I was not prepared to go through it again so I have put a bypass plagte in place with a traditional air cooled cooler out the front.

    The last one put in mine didn't even last 12 months yet it is still on original radiator whihc is not showing any signs of issue.

    On the Jeep at least it is hard to get to but with a bit of contortioning can be removed without removing the manifold but we have a different manifold.
     
  14. oigle

    oigle Senior Member

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    So, Fester, you have had yours off and had a good look at it, I assume. Can you describe the internals for me? Does it cool the engine oil as well as the auto tranny oil?
    What actually failed in yours? Did you have mixing of oil and water?
    I have been tempted to add an extra auto cooler as my auto oil gets quite black in 70000 km, which indicates it is getting too hot. I was going to plumb an extra cooler into the present system so that the engine coolant would keep the auto oil from being too cold in low stress usage and of course warm up more quickly. It really should be kept within a temp range - not too hot or too cold. Haven't heard of any MB systems failing in that heat exchanger area on the 270 motor. Maybe some techies might know better?
    Could you detail what you did with a "bypass plate"?
    You said "coolant was changed as required". That can be taken many ways with the supposed long life of some coolants. As I said in a prev post, I do mine evry 2 years whether it "needs it or not".
    Thanks mate
    Ian.
     
    Last edited: Jan 11, 2013
  15. fester

    fester Guest

    The coolant was changed every couple of years. the PO did not believe in long life coolant and neither do I.

    They fail by way of corroding or breaking within the internal core. I haven't pulled mine apart but they look like a mini radiator or more like an intercooler core. When they fail they start dumping engine oil into the coolant as engine oil is under higher pressure than coolant. I've never heard of one mixing water with the oil. In the Jeep they run and expansion tank and then an overflow bottle so typically you see it in the expansion tank being the highest point and then oil leaks dumped out around where the overflow is located as the excess volume in the system is pushed out.

    They do not cool tranny oil only engine oil. Mount directly to the timing case with 3 matching passages and one external water outlet that links back to ghe block with a rubber hose. I say outlet but I never found a schematic to show the actual flow direction.

    As far as my research shows they are all the same on every 2.7 whether ML Jeep or Sprinter. Not sure if only happening to Jeep but the incidence is very rare when I googled, although I have now come across about 5 Jeep incidences.

    I too have the idea of an extra tranny cooler int he back of my mind, nearly did it when doing the oil cooler but bit sick of it and it's going to be tighter for me now with where the pipes run for the engine oil cooler, otherwise I had the perfect cooler on te shelf to fit the spot perfectly and plumbing in the Jeep would be quite easy. My bypass of the oil cooler is quite simple but quite involved due to the space constraints.

    Some pics might help:
    [​IMG][​IMG][​IMG]

    WE have a CNC water jet cutter at work so I drew up the shape of the original and cut it out of 32mm ally plate for some reason though I didn't save the photos i took of it. I used 32mm so I could bore a passage from top to bottom for both oil and water then cross drilled into it and welded up the end holes basically making an internal passage to take the water from top inside to bottom outside and so i could have the in and outlets for the oil closer to the middle of the plate. This is becuase there is very little room for fittings and piping to clear the manifold and come around the power steering cooler. As it was i had to cut and weld a couple fo fittings to get the right clearance as it needs a tight 90 degreee swivel fitting cause they can onyl be screwed in in place. I had to cut and bend my own pipes to make my own hydraulic fittings. Water was easy just a tapped in hose tail with an ebay 90 degree silicon bend cut down a bit to join the cooler back to the block fitting.

    This may give a bit of an idea though, yoou can see it just there behind the oil filter cap:
    [​IMG][​IMG][​IMG][​IMG]

    The trans cooler i want to use is a second power steering one and it fits perfectly there on the passenger side where the oil cooler pipes come past just not sure now whether there is enough room behind the grill.

    Ian just a side note are you doing your own trans oil changes and if so what oil are you using and where do you get it.
     
    Last edited by a moderator: Jan 12, 2013
  16. grober

    grober Senior Member

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    To be honest its more likely to be an oil" heat exchanger " rather than a "cooler "---possibly to get the engine oil up to a stable operating temperature faster in cold conditions rather than cool it down.;)
     
  17. oigle

    oigle Senior Member

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    Yes. For sure, it works both ways.
     
  18. oigle

    oigle Senior Member

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    Fester - thanks for that great breakdown. I always thought that my auto oil went through the heat exchanger - pipes go up into that area but very hard to see just where they go. If the auto oil doesn't go through there, where on your Jeep is the auto oil cooled? Is there a bottom tank in your radiator? Could easily be different on the MB in that area. I have no other cooler other than the "low temp radiator" which carries coolant - not oil. I assumed it was for the auto oil and possibly also the engine oil. Seems I need to do some more research or have some kind indie tell me how it works. I have not heard of any 270 motor in a Benz that has had your problem.
    I have always bought the special synthetic oil from MB. Exxy but cheaper than trannys. Can't drain my torque converter so can only change 4.5 litres at one go. I did it at 60K and again at 130K. Was blacker than I liked the 2nd time. Bit more km's and some original oil still in there. Intend to do it every 50K from now on. A good cooler setup would help prolong the oil life for sure. It is on the list. I think it is only because I do a lot of towing that it is an issue. Only tow 1600KG so wonder how MB claim it can tow up to 3500KG. That would kill it for sure.
     
  19. HERBIEMERCMAN

    HERBIEMERCMAN Senior Member

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    i think grober is correct, the ali element is for faster heat up of engine oil, most vauxhalls have this totally inadequate poorly designed heat exchange element, very thin ali separator plates. i just bypassed the element on my daughters car with good rubber pipe and clips. you clean out your engine by running it for a few days with dish washer tablets in the cooling system, they do not foam and really break down the oil in the cooling system, especially important for the heater matrix to be cleared of oil sludge etc. i was told by a designer that the component is more trouble than it is worth and only really comes into its own in very cold climates.

    on my merc there are two oil coolers, constructed with 2mm dia guild tubing, long lasting, one for engine and one for autobox oil, located below the two headlights in the wing cavity, they are only fitted to the 7 seater model that also has the towing package in the order spec, they are both air cooled fanned, but have never activated since i have had the car from new 15 yrs ago, merc design to the worst case scanario, eg, me towing a heavy caravan and 7 people on board in the sahara. hope this info helps, good luck. herbiemercman.
     
    Last edited: Jan 14, 2013
  20. fester

    fester Guest

    Yes on the jeep the trams is cooled through a traditional exchanger in the bottom of the radiator. I was tempted to just do a bypass loop with the cooler mod, would have been easier, but every listing or detail I read about it called it a cooler so thought I would err on the safe side. I tow in our heat as well so thought that was a better although harder option.
    The jeep also has a steering cooler as the coolant fan is hydraulically driven. One of the jeep guys is about to play with a trans cooler. It's a B & M one with fan but he intends to block off the radiator exchanger and I don't agree with that even if the trans one has the fan. It's still only about 300square which I think is still not big enough to work alone fully.

    I'm not opposed to the MB fluid for a change at say 5litres x $25 but I have a small trans issue and wanted to flush most of the old stuff out so 15 liters x $25 hurts a bit. I'm having an issue with the trans shutting down and dropping into netural with engine shut down as well. Not often and random. Previous owner ran a specced Penrite oil with no issues and I recently changed to the Nulon but want a true approved MB oil to cross it off as a cause.
     

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