Welcome to another Extreme Rigs D5 Pump Top review. Today we have the recently released Alphacool Eisdecke D5 Pump Top to run through it’s paces. Eisdecke is the German word for “icecap” and we have noticed at least one online retailer listing the top as “Alphacool Icecap“, however we’ll stick with the name as listed on the packaging.

We have the black acetal version to check out which has kindly been loaned to us by one of our good mates. Two versions of the Eisdecke D5 top are available, black acetal, and also a clear plexi version. Our acetal sample is brand new and unused, however our good friend couldn’t help himself and rifled through the package to check it out before forwarding it to us for testing and review. Therefore some of our un-boxing photos are not exactly the same as you would find when un-boxing your own.

Nearly 3 years ago we tested Alphacool’s HF D5 top. While the performance was decent, we could not recommend it at the time because of issues with the seal and that it leaked without over-tightening the retaining ring screws which led to stripped threads on the top. Hopefully with this generation top from Alphacool we won’t have the same experience.

Today in our review of the Eisdecke D5 Pump Top we’ll do an un-boxing and describe the included parts, a step-by-step assembly, run through the data from the extensive performance testing and finish off with a summary.

While not sponsoring the Eisdecke D5 pump top for this review, AquaTuning and Alphacool are regular sponsors of Extreme Rigs reviews and we look forward reviewing more items from the ever expanding Alphacool range in the near future.

AquaTuning logo

Let’s start with our un-boxing of the Eisdecke D5 Pump Top and see what we have to work with.

The Eisdecke D5 Top comes packaged in a sturdy box which differs little from how the previous generation HF Top was packaged.

It is likely that Alphacool use the same box for each of the tops in their new range of Eisdecke Pump Tops, as the identification label is a sticker on the lid, while the sides have Alphacool branding only.

Flipping the lid we found another secondary cardboard flap is protecting the parts inside.

Under the second flap were 2 x instruction sheets. One has instructions and information about fitting an Eisdecke DDC/D5 Single Reservoir (which we didn’t have) to the Eisdecke pump top .

The other is specific for the Eisdecke D5 Pump Top and details the assembly of the top with a pump in an easy to follow step by step format.

Under the instruction sheets we found the pump top itself.

Please remember that our sample, while being new, had been rifled through before we received it to photograph.

We found out later that the Pump Top was indeed shipped in it’s own sealed plastic bag which had been removed prior to us receiving it for the review. Likewise the pump retaining collar was in it’s own bag which we found already attached to the pump top (or maybe the collar was in the same bag as the o’ring which we found tucked inside the pump top).

At the bottom of the box was two mounting brackets which are bagged separately and another small zip-lock bag containing some screws and an Allen Key.

The three stop plugs which were already fitted into ports on the top, were originally in the bag of screws as were the 8 screws for the retaining collar.

Above is the complete kit as we unpacked it (not factory packed), while below is everything that was in the box, unpacked and broken down.

The instruction manuals are detailed enough yet have easy to follow instructions and we’ll take a closer look at the relevant sheet in our step-by step on the next page.

Firstly, let’s take a closer look at each of the parts.

Firstly the pump top.

Immediately we notice the number of G 1/4 ports that is available, 5 in total. There are three inlet ports to select from and 2 outlet port options.

While three inlet port options is fantastic, we can’t help but notice of that on the top face there is not a centralized inlet port. In our mind a centralized upwards facing port is alienating many potential buyers who want to fit a tube reservoir directly to the pump top with a male/male fitting.  While of course such a reservoir can be connected – it will be off center which is less attractive.

Alphacool do offer a D5 Top/Tube Res Combos in their updated pump accessory range, the Eisbecher D5, but it is a completely different top to the Eisdecke D5 which we are looking at today. We like multiple port options for sure, but we like them incorporated in the design, not having to purchase additional or alternate products to do something which could be achieved with better design in the first place.

If it was my top to play with, I would seriously consider drilling through the center and tapping my own port as there is probably enough material for a G 1/4 thread, but it would be close – attempt at your own risk!! but please let us know how it goes if you do try the mod.

Alphacool Eisbecher D5 Top/150mm Reservoir Combo

The Eisbecher D5 Top with 150mm Reservoir is similar yet different in so many ways to the Eisdecke D5 Top.



We concede that Alphacool do offer a reservoir which does attach directly to the top face of the Eisdecke D5 top. The “Eisdecke DDC/D5 single reservoir for Alphacool Eisdecke top” is an option which can be purchased separately and we do like the look of it for the most part, but we feel confident in saying it will not suit the style of every build and seems aimed towards small form factor builds where space is at a premium.

Not being able to attach a tube res on top of the Eisdecke top seems like a missed opportunity and will likely be the main reason many potential buyers will look for an alternative D5 top. In confined spaces however, this combo could be a real lifesaver and may well attract many potential buyers because of the very small overall size of the unit, (although the large G 1″ port at the top has us scratching our heads again).

Eisdecke Res

Apart from the five G 1/4 ports, there are also a lot of other holes which have been machined in the Acetal top. The holes in each corner of the top face are for attaching the Eisdecke reservoir as seen in the previous photo. When the optional reservoir is not fitted these holes are simply left vacant. Not exactly elegant in our mind.

The same goes for all the holes on both sides and the rear face where there are sixteen holes machined in the Acetal top. Surely a mounting system which utilized one set of holes would have been a better thought out option.


The 12 smaller holes on three sides are tapped with an M4 thread and are used for mounting the top into your chassis. The standard installation uses only 4 of these holes, so most of them are unused detracting from the look of the unit when fully assembled.


Our biggest complaint about all the holes machined into the Acetal top surely must be about the two larger holes on opposite sides of the top. They are for installing single 5mm LED lights which “might” end up looking fantastic on the Plexi version of the Eisdecke top, but on the Acetal version these holes should not be there at all.


Looking into the volute we see a nice deep 1/2 round channel for the fluid to exit. However we have concerns that the impeller of the pump will be sitting up a little high as the center inside the top is raised up quite high rather than being “coned” in. This could contribute to less than optimum performance, however it is similar to most D5 tops on the market, so at this stage we think it’s likely to at least be competitive in it’s output capacity.


All the internal machining is very smooth and we can not really fault any of the surface work. The outside surfaces also had an excellent finish with the exception of the 4 the edges of the sides.


Seemingly as an afterthought the four edges have been chamfered, which is a nice finishing touch, but on our review sample all the chamfers were noticeably rough compared to the rest of the surfaces.

Eisdecke Chamfer-101Eisdecke-D5-Parts-143

The pump collar ( or pump clamp) is a plastic of some kind which has been made by injection molding and is a bolt on type of collar. We prefer a bolt on collar over a screw down collar as they just seem less likely to become loose during operation and the constant vibration of the motor.

The Eisdecke D5 collar employs eight screws in four sets of two, placed in a cross pattern. This screw hole spacing pattern leaves quite some distance between holes so hopefully we won’t run into leaking seal issues for our testing. It seems unlikely as the collar is quite stiff with virtually no flex and therefore should hold it’s shape well when clamping down the pump.


A set of two stands is supplied with the Eisdecke D5. The stands seem to be a multi-purpose stand/bracket and for fitting them to the D5 Eisdecke only the top two elongated holes are utilized.

At this stage (un-boxing) it appears that the brackets can be used to mount the pump/top horizontally on the chassis floor / mid-shelf or vertically to a chassis wall panel or perhaps even a radiator mount. We’ll explore these options further in or step-by step assembly on the next page, however it does appear the stands are only able able to mount the top in a horizontal position if they are secured to horizontal panel such as a the floor or mid-shelf. Not being able to orientate the top vertically in this very common installation scenario seems like an oversight. While the end user could easily overcome by drilling another hole on each of the stands, we do believe this mounting option should be there already.


Each bracket/stand has the familiar blue Alphacool logo and 4 x M4 screws are provided to attach the brackets to the top.

The included screw sets include the 4 x M4 x 8mm screw for the brackets we just mentioned. A strange inclusion is 4 x M4 x 40mm screws which are used to attach the optional Eisdecke reservoir. To us it would have made more sense to include the 40mm reservoir screws with the reservoir rather than the pump top. Maybe they have another possible function which we are not yet aware of.

Also included but not photographed with the other hardware below are the 8 x M4 x 8mm screws for the pump collar.

Three brass port plugs with a black finish are included to cap off the unused ports on the top. The port plugs are packaged in the bag of screws from the factory which seems a likely cause for the scratches on the finish of our samples.


Conspicuous in their absence is any form of decoupling for mounting the the assembled unit into the chassis. It seems Alphacool are leaving the end use to provide their own if keeping pump noise is important to them. D5 pumps are very quiet when decoupled, but coupling directly to the chassis can increase the noise significantly.  Maybe it’s a assumed that Eisdecke D5 purchasers will reuse an existing mount kit. Whatever the reason we would have preferred for a kit to be included with the Eisdecke D5 package.


So we have all the pieces, let’s see how easy (or difficult) the pump installation process is.