I'm pretty sure the black stuff is from your Norpene Tubing. No idea if it is a plasticizer or the rubber compound breaking down but mine has done it as well. All my copper blocks have a black film/oxide layer that requires a fair bit of work to get off. As far as I can tell my fittings, res and rads are all clean. It's usually only in the fins of the raw copper blocks. CPU blocks have seemed more susceptible. I haven't bothered with cleaning them since the first attempt. My temps are fine and I'm lazy.

For the pump I don't know what to tell you. Try laying the pump "on end" with the inlet up and see if it still makes that noise. Maybe try just the pump on it's own just pushing water through a bucket or something?

 

Get a better pump if this one keeps dying.

 

@animal0307 ok, that's encouraging to hear (so to speak). Which tubing do you recommend? I know of the LRT advanced but heard of problems with it. What about the new EK ZMT or the new Mayhems Ultra Clear tubing (which is also said to be plasticizer free)?

Changing the position of the damaged pumps made no difference. The impeller receded too much and is hitting and scratching the body regardless of the position it's in.

@JackCY, the first two pumps were killed, those pumps are gone. I got a 3rd new one, which I'm sure will die in the same way if I don't fix the problem. The problem is elsewhere in the loop, hence my post to try and figure out which is the culprit.

 

I may be wrong about the tubing. I'm no pro with plastics and the like. Just like you I hard that the Norprene doesn't have plasticezer and I like the malleability/feel/look of it over standard tubing choices. I just assumed the scale/film or oxide in my blocks was from the tubing since my loop is raw copper, stainless and chrome fittings. But since it wasn't clogging anything I wasn't going to worry about it.

I have takena bit more time to look at your pictures. It look like the bearing on your pump is shot. What does the inside of the impeller look like? A quick Google search reveals that that the D5 impeller is a graphite composite. I wonder if the impeller's bearing surface "exploded" and that's what the black stuff in the coolant is graphite particles? My tubing has never turned the coolant black like that and I've been using the same tubes for ~4 years with 6 month average water changes.

Data sheet: http://www.hvacquick.com/catalog_files/Laing_D5_Vario_Specs.pdf

 

Two pump dying in the exact same manner after pretty much the same amount of time suggests a consistent and permanent cause, not a faulty pump. The impeller inside looks "fine", in that you wouldn't be able to tell there's something wrong by looking at the inside of the impeller, I made some photos for you below (click to enlarge) ...

It's only when you put it back in the body and notice that it receded (see the comparison with the new and identical pump) that one realizes the middle spherical hole in the black graphite (the one that sits on the ceramic sphere pin of the body) has worn out, hence causing it to recede and hit and scratch the pump body.

Something caused higher friction between the white ceramic sphere of the body and the graphite of the impeller in porder to kill it like this in 6-9 months. Hence it must be something that makes the coolant more abrasive than normal, since the coollant is the only agent coming in contact with the impeller.

The tubing was my main suspect, but now I'm discouraged by you saying you ran it with Norprene for 4 years without killing your pump. Was it the same tubing, i.e. Tygon R6012?

It could be the pump top, or the metal polish I applied 1.5 years ago inside the cpu block (see my 1st post), which could be gradually scraping off. I regret doing that regardless. I doubt it's the nickel plating itself (nickel is ferromagnetic and hence all particles would stick to the impeller which is a huge magnet).

I've already ordered new Primochill LRT Advanced tubing, a new reservoir and the new VPP755 pump by Alphacool, which is compatible with the D5 but has a very different shaft and impeller design, and so it's unlikely to be destroyed in the same manner. I'll also wash the copper rad again with acid over 24-48h and then put the loop back together. After 3-6 months I'll drain it and if the coolant is again black then it's definitely the cpu block (either the metal polish or the plating), in which case I'll just buy an all-copper block. If the coolant is not black but the pump gets killed, then it's the pump top, in which case I'll get a new one.

Watercooling is quite fun and allowed me to push past 5 GHz, but man is it costy, a pain in the ass, not to say riskier ... I still enjoy it though



EDIT: Here's a couple of more illustrative photos. Pay attention to the visible part of the white ceramic ball and how thin the black graphite is on top of it (left and right side of it). The new pump is now in the loop so I can't take a photo of that as a comparison, but it surely must be must thicker (given the photo above comparison the two pumps).

Click to enlarge:

 

I can't quite tell from the pictures, but is the pump scratches on the first one only in one area on both the impeller and the housing? and not all around both? If so, that seem to indicate bad part fit tolerance on both parts so that only those two area are worn. But that doesn't explain both pumps.

Do you know what the root cause of the failed pumps are? Is there burn marks on the electronics?

Also, is there any other evidence that the impeller is being worn by the pump top?

 

You need to click the images to enalrge them. As I described, scratches are on both the impeller and body (obviously). For the 2nd pump it's not all around because I stopped it immediately since i was nearby. For the 1st pump it's all around becuase it ran like that for a few minutes. It's not bad fit tolerance, and they both ran fine for about 9 months. I don't know the root cause, that's why I'm posting, but I explained some suspicions ... you should read the posts.

There is evidence it's being worn, but not sure if it's from the pump top (like I said, you should read the posts). I actually emailed EKWB who manufactured the pump top, and asked them, also pointing them to this thread. Will see if they reply. That pump top is old and was superseded by a Rev2 then discontinued - I don't know how popular it was but I haven't found any reports about problems associated with it.

 

it looks like damage from the impeller being compressed, it is possible that the pump top is causing this to happen. try a bitspower pump top with the new pump, I really thank that this will solve the issue.

 

as for the black stuff, it's not the tubing, I have been using norprene tubing for 6 years, and have never had it blacken my coolant. I use a antifreeze mix so I leave the coolant in my system for years at a time.

 

Quote:

Originally Posted by mastabog

You need to click the images to enalrge them. As I described, scratches are on both the impeller and body (obviously). For the 2nd pump it's not all around because I stopped it immediately since i was nearby. For the 1st pump it's all around becuase it ran like that for a few minutes. It's not bad fit tolerance, and they both ran fine for about 9 months. I don't know the root cause, that's why I'm posting, but I explained some suspicions ... you should read the posts.

There is evidence it's being worn, but not sure if it's from the pump top (like I said, you should read the posts). I actually emailed EKWB who manufactured the pump top, and asked them, also pointing them to this thread. Will see if they reply. That pump top is old and was superseded by a Rev2 then discontinued - I don't know how popular it was but I haven't found any reports about problems associated with it.

Sorry, I'm color blind, and there isn't enough detail or contrast for me to tell accurately. I guess I also missed your description...

I'd take the pump apart and look at the board to see if any parts are scorched, burnt, looks like they were exposed to high heat, melted, ect. If there was rubbing caused from the top, it will make the components work harder as there is more back emf that is generated by the friction.

 

Agreed it does sound like a systematic issue that is killing the pumps consistently.

I don't remeber if it's Tygon tubing or not but it is branded with the Norprene name and copyright so if it's Tygon that makes it it's probably the same stuff you have.

When I said the bearing "exploded" I mean that the graphite part in the impeller where the ceramic ball rides had worn out and the shaving from the bearing wearing away is what was floating around in your loop and that's why the coolant was black.

I've never had nickle blocks so I cant speak for the flaking or damage it might do in a loop. I never could justify the price or got over the peeling issues from years past.

As for the metal polish. I'm thinking that's what aided in your pumps premature death. I'm not sure why you need to polish the inside of your blocks but if you did that it would very easy to get the stuff stuck in the fins and then introduce the grit to your loops. (I wonder if the Aurora coolants from a few years ago developed the same pump issues?)

Any way. I hope you have fixed the issue and that your new pump last a lot longer

 

@Toolmaker03, If I may ask, what are all the components in your loop, and which coolant exactly are you using? Do you also use nickel blocks and fittings with your norprene? I'd be glad if the norprene tubing is not the issue (I like its flexibility).

A tricky question: what's a safe distance (mm) between the impeller and the pump top?

You know, the black stuff could actually be graphite dust, from the impeller's graphite that got worn out ...

@animal0307, yes, in the photos in my last post (or below) you can see how thin the graphite became at the top of propeller, the part that sits ont he ceramic ball. It was clearly worn out. Something made the coolant abrasive, and I have yet to figure out what exactly. Click to enlarge:



So the suspects so far seem to be:

- Pump top? I'm starting to suspect this a little more than before. The impeller definitely does not touch the top though.

- Tubing? @animal0307 has norprene and blackened coolant too (but not sure if from the tubing), but @Toolmaker03 has been running norprene for 6 years without issues.

- Metal polish? it should have gone by now given I drained and filled the loop at least 6 times since I applied it, though the polish itself is pretty gooey. I kind of doubt it could blacken the coolant to the same extent twice over 1.5 years, but it might have. If yes, then EK gave the completely wrong advice!

- Nickel plating of the block? What's the peeling issue you speak of? Sounds a little scary. My EK block is from 2012...

- Rad or res? Pretty sure it's not at fault here.

I was planning to put the new VPP755 pump into the old top, but I'll likely order a new pump top too.

 

The black colour of the coolant is simply the graphite from the impeller bearing.

This sort of problem is very unusual and can normally be traced to a bad pump position or something similar.

That doesn't seem possible here though.the pump has a good connection to the res and is sitting in an orientation that ought to make air gathering inside it near impossible.

I can only assume the pump top is bad somehow.
The top actually pressing on the impeller is very unlikely because it would be unlikely to turn at if that were the case.
To get 3 years out of the first pump and 1 out of the second would seem to indicate that it isn't a severe problem or we would expect failure in hours rather than years.
Could it be the initial filling and bleeding process? If when filling the loop the res level drops enough to let the pump such air it can air lock the pump which can then be difficult to clear again. Running for only a short time in an air locked state could cause just enough excess wear that over time is made worse till the bearing wears through to that critical point of contact.
I only suggest that because I know how difficult it can be to fill a loop with a res that small. You need to be quick on the power switch to stop the pump sucking air.

 

Quote:

Originally Posted by mastabog

SNIP*

So the suspects so far seem to be:

- Tubing? @animal0307 has norprene and blackened coolant too (but not sure if from the tubing), but @toolmaker03 has been running norprene for 6 years without issues.

No, I have NEVER had my coolant turn black. I have had a black skin/film or oxide develop on my water blocks. But never a build up or anything that looks like it's leeching from the tubing or some other component breaking down in my loop. I think it's more likely an oxide building up on my blocks because it doesn't come off easy like a goop would.

 

@Ashcroft, Thanks for the comments. I too was suspecting the black color may be graphite dust from the impeller that was worn out. I used to have to be quick on the switch when filling the loop via the res, but now i fill it via the rad and it's much safer! See pic below. I open the two ports circled in green, and I fill the rad fully via the top green port, the coolant filling the rad, and then flowing down via the yellow line, until both the rad and the res are filled ... this ensures that the pump is also filled up fully without any air, theoretically (it's sitting below the res), including the tube above the pump too (up to the top level of the res, which has that green port open). This fills up with coolant most of the loop, which doesn't require to be quick on the off switch. Last time I didn't even have to switch the pump off after this first step - the coolant level in the res did not drop fully, as there was less air volume in the loop than the res volume - I just closed the rad port and filled the res back up. I was quite proud of myself

The pump top was never touching the impeller, I would have heard that. But if the pump top design is flawed, then I wonder if the flow of coolant in between the pump top and the impeller could cause uneven pressure on the impeller, leading in time to the impeller's graphite to wear out ... this is just speculation but the fact that EKWB released Rev2 of this very pump top shortly after I purchased it, then discontinued it, makes me wonder.

Question: As you can see, the pump sits on that pink sponge (to absorb vibration and noise). The pump is not fixed to the case, so I wonder how much of its own vibration (felt in the ceramic ball and axis too) could contribute to the wearing out of the impeller's graphite? How many others run their pumps like this? Does everyone fix the pump to the case?

 

OK, so yeah that all sounds good. I have seen cases where the pump is positioned like yours but they use the front outlet and pump downward so the pump naturally traps air.

It is possible it is the top itself. You mentioned a thicker oring? I wouldn't expect that to be a major concern but it might make the position or height of the impeller change the flow dynamics just enough to cause a little imbalance. Which then over time can let the impeller wobble more than it should. Its likely to remain speculation I'm sorry.

I did hear a rumour that there were problems with the older EK dual d5 tops. Supposedly the D5 was changed slightly in dimensions too but I have never had that confirmed and I don't entirely believe it.

 

@Ashcroft, many thanks for the input. If i recall from 4.5 years ago, the thicker o-ring came with the EK top and EK instructed to use it (can't find a pdf of it online). Imay just get a new pump top for this new pump I ordered (an improvement over D5, solid reviews here and here), which is supposedly compatible with most D5 tops, but as the reviews pointed out, not all D5 tops.

I haven't yet ordered a new top or block. @Toolmaker03, If I may ask, what are all the components in your loop, and which coolant exactly are you using? Do you also use nickel blocks and fittings with your norprene? I'd be glad if the norprene tubing is not the issue (I like its flexibility).

 

well the GTX580 water blocks are nickel plated, the CPU block is copper

ok, so I did a cost out for this build as is it now, and I did a cost out for the upgrades I am adding to it.
the current build.
$400 PC case
$25 PC case fan wire extensions.
$30 PC case vandal power & reset switches
$40 4 strips of PC case CCFL lighting
$90 6 PC case fans corsair 120mm AF fans
$18 3 PC case fan filters
$70 PC case G-vans fans & light controller
$30 Asus DVD drive
$25 3.5" FP USB hub
$200 Asus sabertooth 990FX mobo
$150 FX8350 CPU
$1000 2 X EVGA GTX580 video cards
$283 Enermax 1350W PS
$220 Two intel 520 120G SSD's
$80 Samsung 8G 1600Mhz DDR3
these are the actual PC components.
$273 13 BP soft 90 3-way fittings
$116 4 BP 1/4 turn valves
$36 6 BP 25mm extensions
$80 10 BP male to male rotary fittings
$16 2 AC T-fittings
$16 2 PB 50mm extensions
$100 10 KL 3/8" X 5/8" compression fittings
$50 XSPC raystorm CPU water block
$212 swiftech GTX580 water blocks
$180 Two ST D5 pumps
$53 BP D5 pump top
$50 BP D5 pump top 250mm reservoir upgrade
$50 RH 250mm metal reservoir cover
$23 BP inline flow meter
$15 XSPC inline water temperature sensor
$90 6 corsair 120mm SP fans
$18 3 120mm fan filters
$127 Monstra 360mm radiator
$25 KL radiator mount
$28 2 BP 120mm fan to reservoir mounts
$50 2 radiator fan shrouds
$15 6' of 3/8" X 5/8" norprene tubing
$12 2 reservoir black lights
these are the water cooling upgrades added to the system.
the total for the build is currently at $3,422
now for the upgrades and replacement parts.
$127 Monstra 360mm radiator
$90 6 corsair 120mm SP fans
$168 8 BP soft 90 3-way fittings
$30 6 120mm fan shrouds
$96 Two KL radiator mounts
$58 2 BP 1/4 turn valves
$15 5 120mm fan filters
$16 2 BP 50mm extensions
$40 4 male to male rotary fittings
total for the upgrades $738
replacement parts
$220 FX9590 CPU
$90 2 X D5 strong pumps

I think this is everything.

.

 

Ok, it's settled. EKWB saw this thread and confirmed that it's caused by a design flaw with their 2012 pump top. I'm posting here the two emails because i think they deserve some credit for being both honest and generous:

Quote:

Quote:

Dear EKWB,

I've been experiencing an issue which killed two D5 pumps in exactly the same way. I use mainly EKWB components: pump, pump top, fittings, reservoir, CPU block. Something is causing the pump impeller to recede over time, and then the impeller starts hitting and scratching the pump base, making a horrible rattle sound and obviously dying out.

I am using the original EKWB D5 acetal top purchased in 2012. I know you released Rev2 shortly afterwards and then discontinued it. I wonder if there were any design flaws/faults with the original D5 top.

I posted the details of my problem here, along with a video and pictures of the pump and the impeller -- please pay attention to the photo showing the damaged pump and a new pump (they were identical when they were purchased), and note how the damaged one has a receded impeller: http://www.overclock.net/t/1621836/somethign-is-killing-my-d5-pumps-and-turns-the-coolant-black-please-help#post_25804300

Can you tell me if the old EKWB pump top has any design flaws that could cause this over time? I'm wondering if it puts too much pressure on the pump's impeller, causing the impeller to recede over time and then hit the base.

Many thanks in advance,

Dear customer

Thank you for contacting us.
I'm really sorry to hear about the reported problem.

Yes, sadly that is indeed the case here.
These old D5 TOPs had some design flaws and you should replace it with a new one. Sadly this top is from 2012 which is WAY past the warranty coverage, so you won't be able to replace it under warranty.
To compensate a bit, I can offer you a 30% discount for a new replacement top for your pump - https://www.ekwb.com/shop/ek-xtop-revo-d5-acetal

Or, if you need the pump as well, you can than of course get this one - https://www.ekwb.com/shop/ek-xtop-revo-d5-pwm-incl-pump
The discount still applies, of course.

Please let me know and I will arrange it for you.

Many thanks once again EK, great customer support even after 4.5 years. Pity I didn't think about it the first time it happend, I could have saved myself some money sooner.

@Toolmaker03, that's some list! ... watercooling sure is an expensive, and bloody tedious, hobby.

 

Prestone 50%/50% antifreeze the green stuff. I mix that with another 50% distilled water making the total mix around 30% antifreeze and 70% distilled water.