Cleaning and repairing my Koolance Exos2 watercooler

     So a while back, I bought a Koolance Exos2 for my old socket 478 Pentium gaming rig. It served me wonderfully for 3 or 4 years, and then like a dummy I ignored Koolance's warnings not add color to the coolant, bought a syringe of color, and added it in. A few months later, I went to add more color and accidently grabbed a syringe of arctic thermal paste and put that in. Stupidly. Well stupidity aside, my system still ran for a while, but recently (about 2 years later) it finally clogged up, and gave up. While I don't use liquid cooling on my current rig, the Exos2 was a great system and it seemed a huge waste to just throw it out, so I decided that I would attempt to clean and repair it.
     I write this not so much as a guide but more of a log of what I did along the way in case this helps anyone who is in a similar situation to me with a clogged/dirty/broken out of warranty liquid cooling system like this one. I encourage anyone with similar stories, or thoughts/tips/tricks to please comment on how you fixed your situation.

First, the wonderful exos2 itself:

Top View of the main unit. Note the copious sludge in the resevior

    So in my particular case (yours may vary according to your level of stupid. Note: my level of stupid was extreme) there is a combination of problems: Next to zero maintenance of the unit over its nearly 5 year lifespan while running it constantly. Incompatible dye, rogue arctic thermal compound (silver thermal paste), regular build up that can occur in any cooler, assorted sludge and drudge. The Exos2 was build with 2 pumps to be redundant, with one being the intake pump (if you look down on the unit the one on the left) and one being the output pump. It is capable of circulating fluid with only one pump but it doesn't work very well. The manufacturer says that these redundant pumps are to keep things going if one fails, although they really aren't redundant as the unit cant really work with only one pump. Its sort of like saying a car has redundant tires as it can stay level if one breaks; that's true but you cant really drive a car on three wheels.
     Anyways, my return pump was still chugging along like a miracle, but my output pump was jammed up. I also had a problem where if I cranked the voltage up on the fans and pumps to higher than about 4 on the Koolance front panel, both pumps would struggle and stop working. I attributed this to either a damaged control board, or the 2nd pump being clogged and drawing a huge amount of current and basically shorting out the control board. Either way, I wanted this thing to work and I had very little to loose.

CAUTION:Koolance did NOT intend for you to take apart this unit, and while its not impossible to take apart, it isn't easy. You may break it, you will most certainly void any warranty you have; and you run the risk of leaks later when you put it back together. This is not for the faint of heart. Remember, I had nothing to lose with this unit, make sure you don't either.

Dis-assembly:

Important: I am assuming you drained your cooling system before we go any further. If you have not drained the system, you really ought to do so unless you enjoy large, wet messes around your electronics. It should go without saying that since your cooling system is broken (why else would you be reading this?) all elements of the system should be removed from your computer prior to doing any work. That means, all water blocks, pipes, hoses, t-splitters, reservoirs etc. Anything at all that fluid passes through needs to come out to be cleaned. I suggest you drain the system at this time, and since you cannot remove all the water from the reservoir in the Koolance system even after draining, perform all surgery in a tub, wash-bin, or on a number of towels. If you were stupid like me and put dye in your system, it WILL STAIN YOUR TOWELS/CARPETS/CLOTHES. 

There are 8 pretty screws along the top of the unit with nice chromed gromits around them. Nice big fat tempting Phillips head screws...you don't need to take these apart to take apart the unit. They are more or less decorative and they look like garbage if you lose the gromits, so I recommend you don't take them out like I did. You also do not need to remove the fan screws or grills from the top of the unit. Here, Ill provide another picture:

Red indicates screws to leave alone for now, Green indicates remove

I forgot to take a picture of the bottom of the unit, so I will take one when I put it back together and post it here with similar indications, but suffice to say you need to remove all of the tiny black Phillips head screws on the bottom plate of the unit and on the two end-caps. Put these aside someplace, they are very important.  Once you have removed the screws from the bottom plate (your unit should be flipped over) you can remove this plate and you should see something along these lines:

Insides of the Exos2 bottom side. 

Here is a breakdown of what you are looking at:

What nifty labels! Too bad I am terrible with photoshop

• CPU Interface:
  -This is where that lovely little db9 cable connects from the cpu panel. There is a multipin jumper for all of the fan controllers and temp sensors you can install in the PC and a yellow and black 12volt connector from the power supply. 
• Inlet Tube:
  -This is where the water is sucked back into the koolance system. It is attached to one of their nifty little leak free connectors and the other end goes to the intake pump in the reservoir block. 
• Radiator:
  -This massive metal radiator should be pretty obvious. Take care not to damage the grills during your cleaning process. 
• Output Tube:
  -This guy goes from the outflow pump in the reservoir to the output connector on the back of your exos2
• Circuit Board:
  -The controller/driver circuit for the Exos is contained inside an aluminum shell that doubles as a heat-sink for the pump-driver circuit. Little to no care was taken to isolate this from water drips and is one of the few flaws in the design of the whole Exos in my opinion.
• Reservoir:
  -That giant tank you poor your liquid and other things into! its buried beneath other components so we wont get to it quite yet.

Removing the Radiator:

Our next step is to remove the radiator from the Exos2, as it is no doubt incredibly clogged up. To remove the radiator we have to do a few things. We are going to want to unscrew the small black screws on the back panel where the input and output tubes connect. We also need to physically detach the tube from the radiator (output tube). Once you have removed the screws, you can remove the tube. It is connected with a small clamp, similar in function to a jubilee clamp. You can just take a good pair of linesmens or pliers and squeeze the prongs on the clamp, freeing it off the tube:

This is the other side, but the process is the same.

Once you remove the clamp you can choose to pry off the tubing or cut it off. I chose to cut it off, as I planned to replace the tubing, rather than trying to clean it out. Its up to you.

You may need to remove the set-ring around the output port on the back panel, once you do, disconnect the back panel and the radiator will almost be free:

note the screw. noted? good.

Lastly, you need to remove the four large screws that actually hold the radiator in place. Be careful as it is easy to slip with your screwdriver and puncture or destroy the radiator grill surrounding the screws. There are four screws with little black washers around them, take them all out and place them aside. The radiator should now be able to be pulled free from the Exos2 body.

Exos2 Radiator

Set aside your radiator someplace safe for the time being. take care not to remove or damage the felt/foam on the top of the radiator that protects it from damage and limits the noise from vibrations. This thing probably has water/dye in it, so put it somewhere where leaking wont be an issue.

Removing the Circuit Boards:

Next we need to remove the circuit boards that sit on top of the reservoir tank. This is a pretty easy task, there are only a few screws holding it to the reservoir. However, there are a number of wires and connectors going into it and its important to remember what goes to what:

Exos2 circuit board and shield

From right to left front: red and white fan connectors to Exos main fans, Aux Fan connector to your computer, atx power switch interrupt, multipin cable for front control board, temp senor connectors from computer, and lastly the power for the pumps. On the right hand side is a plug for the reservoir LEDS, there is a corresponding plug on the left side. The rear has a 4 pin power connector

Luckily nearly all of these jumpers is labeled on the silkscreen on both sides of the circuit board so if you forget you have a handy cheat sheet in place. Just take some tape or something and label your wires so you know what goes to what. Unscrew the four brass screws at the corners of the circuit board and it should lift off the reservoir. Leave the heat-sink/shield in place for now, and set the whole assembly aside. You can remove the front panel control board now, but I would only recommend doing so if you notice visible water damage to it, or have some other reason to suspect it requires repair. I took mine out to clean it:

Exos2 front panel

to be continued...