Unknown Contaminant in Radiator

schefferd Sep 17, 2013

  1. schefferd

    schefferd New Member

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    Hi Everyone,

    I've got another bit of a puzzle with my Land Cruiser that I'm hoping someone here can help me reason out. A few days ago, I went out to my truck after having a short (15 mile) drive home from work to find a mysterious collection of puddles beneath it. The fluid didn't look like anything I was accustomed to, and I found residue inside the driver's side (LHD) wheel well. Popping the hood (bonnet, sorry!) I found lots of contamination relatively low, with nothing notable from the power steering reservoir, oil filter or oil cap. I did notice a great deal of contamination by the coolant overflow.

    Inside the overflow, I found a mixture that could be best described as melted milk chocolate, or really milky coffee. My contenders for the contaminant are: Automatic Transmission Fluid, Engine Oil or Diesel Fuel. Here are the questions that I'm hoping you can help with. For sake of reference, this is a 2000 90, with a D-4D engine. The only recent work done was an oil change, and replacement of the high pressure fuel pump (see my previous posts).

    Top contender is Automatic Transmission Fluid (ATF). I write it out fully since I had been searching ATF in the search box, but since it is only 3 letters, the search always disregards it. I've seen ATF mixed with coolant many years ago in an old station wagon (gas). In this case, the coolant was routed to the tranny, where a fault allowed it into the transmission. The coolant boiled inside the transmission once the engine was off and came spurting out of the transmission dipstick. My research seems to indicate that on my Land Cruiser, the ATF is routed to the radiator, where there is an internal ATF cooler. Is this generally true? My radiator matches the one for sale at Rough Trax 4x4, and has two quarter inch hoses entering at the base of the radiator (brass fittings, apparently). (Side question, I've never found the ATF dipstick on my LC, is the system sealed?)

    Second Contender is Diesel Fuel. I've never seen coolant mix with diesel, but I understand that some diesel engines have a water jacket that the fuel flows through prior to entering the cylinder. I don't know if this is the case with a D-4D or not. Since the High Pressure pump was recently changed, these events might be related. Could a poorly fitted high pressure pump leak into the water jacket (if there is one)? Could the newer higher pressure be exacerbating a pre-existing leak elsewhere? Does a D-4D even have this sort of cooling element in the engine? I have no idea, and I'm hoping someone here has taken their engine apart and knows for sure.

    Last Contender is engine oil. I know that a cracked block or bad head gasket could cause this sort of problem. There is presently no evidence of water in the oil, and there is no apparent loss of oil in the engine. I also think that oil mixed with antifreeze would look darker than what I'm seeing.

    I've let the LC sit since finding the problem, with hopes that the two liquids will separate out to aid me in identification. If anyone can help me understand what the two fittings on the bottom of my radiator are, or if you know the inner workings of an engine, I'd really appreciate it. I'm planning to take it back to the same shop that did the high pressure pump and the oil change, since this might be related to their handiwork. I'd like to be well informed before I speak to them, so any information you can share would be great! Thanks,

    Dan
     
  2. AndyCook

    AndyCook Well-Known Member I am in scotland

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    ATF cooler is at base of the radiator, there are two hoses connected to fittings.

    Atf dipstick is on drivers side of engine. Near the brake fluid reservoir.

    Unfortunately it sounds like the atf cooler has leaked inside the radiator and mixed with coolant.
    And likely coolant gone into gearbox.

    Best not to drive it anymore until diagnosed, as you could wreck the gearbox.

    The autobox has an atf drain plug on the sump. But this only drains out about 4litres of atf, the other 8 l being trapped in torque converter

    Sent from my GT-P1010 using Tapatalk 2
     
    Last edited: Sep 17, 2013
  3. silvercruiser

    silvercruiser Well-Known Member

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    this is the very high tech atf cooler that runs in the bottom of the rad.

    011.jpg

    here it is in the bottom piece of the rad

    010.jpg
     
  4. wobbly

    wobbly Well-Known Member

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    I would:

    a. Check the atf dipstick, see what the coolant is like, if its the same, its new rad and flush gearbox time.
    b. If its inconclusive, drain some atf from the bottom of the box.
    c. Remove the oil filler cap and have a look in there - if its the head/gasket it'll look similar to the crud in your overflow.

    Whats the temp gauge on the dash telling you?

    Pete
     
  5. schefferd

    schefferd New Member

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    Hey Everyone,

    Thanks so much for your inputs. I was able to locate the ATF dipstick; on the German spec vehicle, it is underneath/behind the air filter, and can only be seen by peering around all that equipment. It can't be "pulled", you have to pull it out from the side and thread it under the filter box to get it all the way out, getting ATF all over the place.

    The ATF has the same chocolatey mix on it, so after a brief hooray for conclusively diagnosing the issue, I need to order parts. I know a radiator is on the menu, but would you all recommend a water pump too? I don't know how easily the ATF might have damaged the pump, but I'd like to save on the shipping if I'm getting stuff. The pump goes for about 80 pounds at roughtrax, and I'll end up paying an extra 20 if I need to order and ship it separately later. Anything else you'd recommend with a new radiator? Roughtrax sells radiator caps, but can I assume the new radiator will already have one?

    Thanks again for all of your help. I'll post some pictures of the swap out in case any newbies like me need to do this in the future.

    Dan
     
  6. AndyCook

    AndyCook Well-Known Member I am in scotland

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    Sorry to hear it is oil cooler failure
    But at least you have hopefully caught it in time, as when this happens to many people the first the know about it, is when the autobox starts playing-up

    you will need a lot of ATF to make sure it is flushed through properly to clear out all the trace of coolant

    i would check with roughtrax whether or not it includes the rad cap - i cannot remember if mine came with a new cap

    not sure about the water-pump - hopefully someone else can advise
     
  7. wobbly

    wobbly Well-Known Member

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    I dont know how much work is involved in swapping a water pump on a d4d, but you may as well if its within your ability, shame to find out afterwards it needs doing !

    Pete
     
  8. fridayman

    fridayman Well-Known Member

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    ATF shouldn't have caused any damage to anything in the cooling system - a decent flush and top up with quality long life coolant will sort out the cooling system. The auto transmission is where you are more likely to have suffered damage - more likely, but by no means for certain. This happened to me, and after a very thorough flush (20+ litres of ATF) I've had no issues at all including towing a camper all over Australia.
     
  9. Ale

    Ale New Member

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    This seems to be a slight weak point in the design for this to be able to happen. Although perhaps not too common?

    I have the same setup in my 80 series, but I was thinking of re-routing the ATF through its own separate cooler rather than through the bottom of the main radiator. That way when either decide to let go its not taking the other out.

    I don't know if many people do this mod, and the efficiency of a separate oil cooler to a combined oil / water cooler, but at least then there is less opportunity for the two fluids to mix.

    A separate oil cooler doesn't seem too expensive, around £100 for an Alisport one, or a lot less if you trust the ebay ones.

    Cheers

    Al
     
  10. fridayman

    fridayman Well-Known Member

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    When I looked into this I was surprised at how many vehicles use this design, and how often it fails. Quite a few Merc's have suffered from the same failure.

    I have fitted an auxilliary ATF cooler inline with the std unit for towing in soft sand, but after seeing the pics above I am going to bypass the std unit altogether.
     
  11. schefferd

    schefferd New Member

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    Hey All,

    The radiator repair has been going along pretty well, so I thought I'd post an update for the benefit of future readers/90 owners. I was able to source a replacement online for just a bit over 100 quid (my keyboard won't make the pound sign, and I don't want to run afoul of the advertising rules in the forum by naming the seller. PM me if you can't find one). The online radiator is a perfect match and comes in at about one quarter of the dealership price, so that is good.

    Taking out the old radiator was pretty easy. The drain valve on the bottom was easy to access and the ATF/Coolant mix came out relatively quickly. There are 4 bolts to undo on the fan cowl, and another 4 bolts holding the radiator frame to the front end. The large water hoses came off easily but the transmission lines were a bit trickier.

    There are two transmission fixtures on the radiator, the return to the transmission sticks straight out, while the feed to the ATF cooler/radiator is a right angle. The return line to the transmission came off without incident, but the right angle fitting disconnected completely from the radiator while I was preparing to break the line free. It took very little force for the fitting to break off, and I'm thinking it is lucky that it didn't break off while I was driving. I think I'd have been out of ATF in a matter of minutes and without coolant and overheating at the same time.

    It is also something to think about for anyone doing an external cooler bypass. It looks like the fitting corroded from the inside contact to the coolant. If you have an older radiator, you'll want to reinforce that connection or just change it out even if you're doing the bypass. Odds are good that the connector will still fail and the radiator will leak, possibly catastrophically, from that fixture. My guess is that the hot ATF in the inlet accelerated whatever corrosive reaction caused the fixture to fail faster than the return. I have some photos that I need to find a convenient place to host for display here. Switching to an external cooler will probably slow down that corrosion, but it won't stop it. It does appear that the fixture can be unscrewed, so it could be inspected during a service check, but if it is close to failing the inspection will probably finish the failure. If your radiator is over 10 years old and you're considering the external cooler mod, be prepared to at least remedy the transmission connectors if not replace the radiator as well.

    The radiator removal and replacement was easy enough, done in under 2 hours with time to take pictures and be careful with help from my Dad who was visiting. Draining the transmission is taking place over a few days now.

    The vehicle had been sitting for over a week, nice and level, before I started work on the transmission fluid. When I cracked open the transmission drain plug, the first 2 or 3 liters that came out was nice clear water. After a minute or so, it was possible to see a thin stream of contaminated ATF flowing within the larger stream of water. Eventually the water drained away, and a good batch of milky ATF drained away as well. Luckily, there was no sign of debris in what came out, so I'm hopeful there was minimal damage to the transmission. My last service was about 2 months ago, and the coolant checked out good at that time, so I know this problem hasn't been going on too terribly long.

    After this, we set up to drain some more out of the torque converter. Holding the radiator inlet line into our drain pan, we ran the engine for about 30 seconds to see what came out. More chocolate syrup and then eventually some air. Confident we had cleared everything we could get access to, we loaded another 3 quarts of ATF into the system and then ran the engine for a short while to blow it out through the cooling circuit. Doing this a second time, the consistency of what is coming out from the cooling circuit is markedly more oily than water, so it is slowly getting better.

    We also decided to do an experiment, transferring some of the bad fluid from the drain pan into a used quart container of the ATF, we let it sit a while to see how quickly the water would separate. After just 3 hours, there was a clear separation with clear water on the bottom and milky ATF on top. We're going to do the drain routine a few more times over the next few days. First drain the water out of the bottom of the transmission pan, add some fluid and cycle out through the cooling circuit to help get some of the moisture out of the torque converter. We're probably also going to get an extension hose so we can dump clean ATF into the return line on the cooling circuit, possibly speeding up the purge.

    If it were an emergency, the vehicle is probably drivable at this point. There is still some ATF in the radiator, which we've been siphoning off the top to minimize the full flushes, and still some water in the ATF. the viscosity appears to be closer to that of regular ATF and the transmission wasn't acting up when I initially noticed the problem; and there was a lot more water in there at that point. If I were stranded somewhere, this much effort is probably enough to get the vehicle home or to a shop. I wouldn't recommend unnecessary travel or distances, though.

    After discussing this a lot with fellow DIY'ers, there was some debate over which way each fluid would move based upon the pressure differentials in the radiator vs the transmission. I don't have any documentation of either, but I'm confident that the real explanation involves a bit more than just pressure dynamics. The flow of fluids during the heating and cooling of both elements and the relative densities/viscosities matter. When I drained the radiator, only thick murky oil came out, but the transmission drained a good deal of clear water first. Since the intercooler is at the bottom of the radiator, and the transmission pan is lower than the radiator, the flow seems to be defined mostly by gravity.

    I'll post some photos to flesh this thread out, and any additional discoveries/observations from the remainder of the transmission flush out. If anyone has any other tips or questions, please feel free to share. Thanks again for all of the help and discussion so far!

    Dan
     
  12. wobbly

    wobbly Well-Known Member

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    Sounds like its going well.

    Debris in the contaminated atf would be unlikely, the danger is that the internal clutchs have been contaminated, but have read similar who have had no long term probs.

    I reckon itll all be fine.

    Cheers

    Pete
     
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