Does anybody know the manufacturer Subaru used to make water pumps for a 2000 Outback?

Not sure; but if you're in the U.S. the OEM pump can be had for maybe $70. Are pumps from other sources much cheaper?

Where can I get it for $70. I can find lot's of ones on ebay for $50 or $60. I'm not sure if I should be using those though.

Whoops sorry about that man. I was thinking of water pump for my '96 legacy (the 'cast impeller' design); that was about $71.

 

For '00obw 'stamped impeller' it was more like $95 for OEM.

There was something that the propellor fits both but one was better in moving water.

I know in pumps for ponds (water + dirt) the propellor (stamped ones) are better than the casted (more less closed propellor)

The aftermarket brand of OE supplier is Paraut. But no guarantee that it's made to exactly the same specifications as the factory unit.

Yes I think the 'stamped impeller' is the 'high velocity' version or something, which can be used in place of the cast impeller pump if desired.

 

Some water pump comparison pics....

 

Are GMB water pumps any good?

It used to be cast was better then stamped, since stamped in theory can seperate from the shaft. Cast on the otherhand, it the fluid isnt changed as it should be, the impeller can erode with time (lots and lots and lots and lots of time).

 

Samped can have this happen too, depending upon what the impeller is made from.

 

Modern engines, this rarely happens, as the waterpump bearing or seal usually goes first.

 

Personally I prefer cast if i have a choice.

 

 

 

nipper

Also, the cast impeller design is a more efficient design IMO.

 

Personally I prefer cast if i have a choice.

 

 

+1.

 

I have never seen a cast impellar rusted to the point where it wouldn't pump water.

 

I've seen this happen on numerous occasions with stamped impellars. I kept the worst one ever, form an 89 nissan Maxima. Nothing but a stump left inside, no circulation, but it didn't leak or rattle. Only clue it was bad was the brown water and the lack of heat in the core.

 

I want to hang it in my shop to point to when people ask me "Can't I just put water in the radiator?"

Are GMB water pumps any good?

I've been running a GMB H2O pump, made in Japan with a stamped impeller, for the past 20K miles with no problems. We'll see how well it holds up. The OEM pump was still going strong with no bearing play or leakage when I swapped it out as a part of the timing belt service.

 

Stamped impellers are more efficient and, therefore, sold as "high velocity" as well noted by porcupine.

Stamped impellers are more efficient and, therefore, sold as "high velocity" as well noted by porcupine.

 

That's not what my intuition would say. I did find this blurb from "Hillier's Fundamentals of Motor Vehicle Technology" which backs that up.

 

http://books.google.com/books?id=DoYaRsNFlEYC&pg=PA106&lpg=PA106&dq=stamped+impeller+vs+cast+impeller+efficiency&source=web&ots=3M_YNECmeA&sig=OYH7fB4yHBsObKWlTCF02Dr9r4o

Check around and see if you can get Beck Arnley locally, they supply an OEM pump.

 

http://www.beckarnley.com/

That's not what my intuition would say. I did find this blurb from "Hillier's Fundamentals of Motor Vehicle Technology" which backs that up.[/url]

Hm that is an interesting book. It says the cast impeller is preferred and flows three times the comparable stamped impeller style. So it's the cast impeller that is the 'high velocity' version?

That's not what my intuition would say. I did find this blurb from "Hillier's Fundamentals of Motor Vehicle Technology" which backs that up.

 

http://books.google.com/books?id=DoYaRsNFlEYC&pg=PA106&lpg=PA106&dq=stamped+impeller+vs+cast+impeller+efficiency&source=web&ots=3M_YNECmeA&sig=OYH7fB4yHBsObKWlTCF02Dr9r4o

Indeed, very interesting, even if my my intuition would say the exact opposite.

 

There have been a couple of interesting threads about this:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=62477&highlight=cavitation

 

http://www.ultimatesubaru.org/forum/showthread.php?t=52560&highlight=water+cavitation

 

So is a97obw's pops wrong? More importantly, is the stamped impeller pump "high velocity," but not "higher" than the cast impeller pump? Weird.

The vanes on a stamped impeller are straight, but not radial.

Not sure what the real engineering considerations are. One of the factors

which limits the pump flow capacity is the onset of cavitation. Perhaps

a non-shrouded impeller is more cavitation-resistant, but I haven't really looked into it.

i worked for Flowserve and Ingersoll-Dresser, both pump manufacturers. the cast impeller shown here would be the most efficient in the case of the hydraulic pumps we worked with, all of which moved water, but of course they were much larger. that knowledge has since left me.

I use the pumps with the cast impeller on all model years. PN 21111AA007.

I have seen to many on the "new version" with stamped impellers leak before 100k miles.

 

Buy a genuine Subaru water pump. JMO

I am not convinced that an OEM pump is different than an aftermarket pump. Subaru buys the pumps from several different suppliers, I suspect they are built to the same specs as the aftermarket pumps. I would be interested in hearing if anyone has any additional information.

 

ATSUGI, Parat and NWP make cast impeller style pumps and GMB makes a stamped impeller style pump.

 

I have done some research on idler pulleys and the situation is very similar. You buy "OEM" idlers from the dealer, but in fact they are made by GMB, NSH, etc. Same exact part.

I am not convinced that an OEM pump is different than an aftermarket pump. Subaru buys the pumps from several different suppliers, I suspect they are built to the same specs as the aftermarket pumps. I would be interested in hearing if anyone has any additional information.

 

ATSUGI, Parat and NWP make cast impeller style pumps and GMB makes a stamped impeller style pump.

 

I have done some research on idler pulleys and the situation is very similar. You buy "OEM" idlers from the dealer, but in fact they are made by GMB, NSH, etc. Same exact part.

 

This is true for some parts, but not all.

 

As far as I know from what I have been told, Parat is the OE manufacturer of Subaru water pumps. And yes, they can be had much cheaper.

But there is really no way to tell if they are of the same quality. The aftermarket pump body is not cast in the same mold as the OE for one thing. If they have to make a new mold to produce aftermarket parts, why not use cheaper bearings or seals in order to recoupe the expense sooner?

Just a theory.

 

One example I am sure of. Genuine Subaru remaned axles are different from the aftermarket axles supplied buy the same company.

 

Not a Subaru part..................but I found out years ago that the center support bearing for Nissan pickup rear drive shafts sold by WorldPac as an OEM part is not the same quality as a Genuine Nissan center support bearing.

 

Basicly what it comes down to is, trial and error.

Yeah, and even if the supplier uses the same molds/parts and so on when producing for the Genuine and aftermarket....do they run the same quality tests?

 

Do they test every part, or just every tenth/hundredth ?

Yeah, and even if the supplier uses the same molds/parts and so on when producing for the Genuine and aftermarket....do they run the same quality tests?

 

Do they test every part, or just every tenth/hundredth ?

 

I worked for an autoparts mfg so I can tell you exactly what they do.

 

Not Much.

 

If they are an aftermarket supplier, they will buy the parts from the same people who make it for 100's of other suppliers on spec. They may physically compare OE and the aftermarket.

 

If they actually make the waterpump, they may test the first ten or twenty, then sign off on the design. From there they never get tested unless they suddenly have a high failure rate or a lot of returns. They may get tested again if OE makes a engineering change, and they get informed about the change. They don't look for engineering changes. This is why its best to buy OE sometimes. Aftermarket doesnt have the resources to watch all the differnt waterpumps out in the market.

 

 

nipper

Good info and insight nipper. Also Subaru in general is a very reliable automaker, so in general their OEM parts are of known good top quality. Now we all know there may be exceptions but in my mind Subaru OEM parts are a good value (when obtained for a good price i.e. Subaru dealers selling parts online). Of if you are talking about particular upgrade parts such as whiteline etc that is a different matter; they are intended to provide a different performance than OEM.

Thanks for the input everyone, I guess in the case of water pumps there is a valid reason to buy OEM parts.