Polo Waterpumps, brands to avoid?

[Deluks]

Seems to be an issue with certain VW waterpumps that were origininally fitted with plastic impellers, which break off at the end of their life. Metal ones are available but It's difficult to find out which ones are metal and which use plastic.

Eurocarparts do Circoli and KWP. Circoli unknown, KWP seems to be fitted with the metal one from what I can gather, Volkswagen original is plastic but they may supply a metal one if you're lucky and are probably the most expensive.

QH are a common brand but can find no info online as to whether they are metal or not.

Anyone heard of/used Aquaflo , Italian supposedly, definitely metal impeller just has a Fisher Price look to it.

 

[^neo^]

Never had any problems in the past with ones from GSF

 

[Deluks]

Ah yeh, was gonna mention GSF but forgot.
They don't state which brand they supply on the website, is it metal too?

I'm swaying towards the Aquaflo, based on the 'guff', particularly words such as 'stainless' and 'military' but what the dickens is 'cavitation'?

The mechanical seal can be defined as the heart of the water pump since it allows the bearing shaft to rotate avoiding the refrigerant to leak out. The quality of the seal is determined by the choice in the manufacturing materials. One of the two sliding tracks is made of hard carbon, a material characterized by high shape stability also at the motor's highest operating temperatures and superb tribologic characteristics thanks to the high percentage of graphite present in this material. The other sliding track is realized in ceramic material with the addition of chemical substances that can ensure long life and a high level of resistance of thermal shock. The structural parts are in stainless steel.

_The purpose of the impeller is to supply the liquid the power necessary to flow along the refrigerating circuit. The special FSP treatment of the AQUAFLU impellers, recognizable because of its particular "flou green" colour, makes flowing easier, protecting the water pump from damages caused by cavitation.

_AQUAFLU impellers are made only in metal for all applications and are realized in casting or pressed steel. A metal impeller can guarantee a longer life than plastic impellers.

_The special FSP treatment of the AQUAFLU impellers is used mainly in the military aeronautical industry in order to protect some parts (i.e.engine, wings, etc.) from the friction caused by the strong impact of the air.

 

[Belle427]

personally i try to stay away from any parts that need complicated guff to explain how they work, as said gsf or euro car parts are normally very helpfull. If you pop to one of their trade counters im sure they will check which of their pumps use metal impellers

 

[Stivino]

Don't worry too much about cavitation, it's something that happens inside pumps. All pumps suffer from it and any decent manufacturer will try to built a pump that minimizes it. They've just used a big word to sound fancy.
http://en.wikipedia.org/wiki/Cavitation