Does water pump blade count and angle matter?

[MNL]

My Duralast water pump lasted 15 years (02 Camry with 2.4) and started to leak so I went to Autozone to swap for a free replacement with the lifetime warranty. The new Autozone pump is from GMB (P/N 170-2470, made in Thailand), and I didn't notice the changes to the blade design until I got home. The old Duralast was a copy of the Aisin pump with 7 angled blades where as the GMB is six straight blades. The blades are about the same size between the OEM and GMB. I check on RockAuto and most water pumps are 7 blades except for the GMP and FVP with 6.

I figure GMB is a large reputable company but am I just over thinking about the effect of flow rate and cavitation with 6 blades vs 7?

 

[Jetronic]

don't think it matters when you've got a partially closed thermostat restricting flow at all times. add to that the rpm variations.....

 

[Escape08]

No

 

[Lubener]

I am surprised your receipt used for the warranty exchanged hadn't faded away after 15 years.

 

[Bottom_Feeder]

I'd be more concerned as to why they apparently use two different gasket types.

 

[SC Maintenance]

Yes the design of the impeller blades affect the volume of flow. I suspect the new one has deeper blades with a steeper angle, so needs fewer.

 

[Hall]

Used to work for a very large chemical pump manufacturer and impeller design is quite complex. Remember in high school geometry people ask "when will I ever use this in the real world?" ? There's more than << that too. Yes, the # of blades, blade angle, etc affects all hydraulic aspects of a pump's flow, but you also can't make a blind comparison that the differences here are better or worse. As SC said, you can change one thing, then change another, and get back to the performance.

 

[Lockasiam]

I am surprised your receipt used for the warranty exchanged hadn't faded away after 15 years.

If you get antifreeze all over them they will bleach. had to warranty a 2az-fe water pump (exact same as op) and come to find out the recepit had bleached from the antifreeze!

 

[Klutch9]

I was just wondering this myself, having had to replace the water pump in my Explorer. OEM has 8 blades, but some aftermarket have fewer blades with different geometry. Ended up getting a Gates which looks similar to OEM. Blade design isn’t quite as curved.

 

[supton]

I'm sure it does but unless if you have training in how to do fluid flow and dynamics and all that, then it's just guessing. I mean, why don't ocean going ships use 16 blades per prop instead of 3 or 4? someone did the math and proved that it was best. Here, it's possible that aftermarket is cheaping out... but how does one know unless if one can stab it in and show a decrease in water flow?

 

[emmett442]

Yes, it matters.

Used to be, on vintage engines, different water pumps were spec'd for AC and non AC cars. This is because fan speed had to change with a condenser added. The accomplished higher fan flow with smaller water pump pulley diameter. Because water pump speed was higher on an AC car, blades had to be changed to regulate flow and prevent cavitation.

 

[MNL]

I am surprised your receipt used for the warranty exchanged hadn't faded away after 15 years.

I have to give Autozone credit here. No receipt needed. They simply asked for my phone number that the warranty might be saved with, typed in the P/N and the pump's purchase date and warranty was highlighted.

 

[doitmyself]

Kicking this down the road, is MNL overthinking this or not? Would most of you assume the 6 blade design will work fine? Believe the product description that states it meets form, fit, and function?

Would it be obvious if the pump under performed? Thanks.

 

[Hall]

Would most of you assume the 6 blade design will work fine? Believe the product description that states it meets form, fit, and function?

No one here can answer that. You have to trust the manufacturer that they matched (or exceeds) the OEM's specs.

 

[Opelman]

I remember getting closed vs open impellers in my youth.

 

[doitmyself]

No one here can answer that. You have to trust the manufacturer that they matched (or exceeds) the OEM's specs.

Thank you. I've gone to the "dark side" of no longer trusting after-market parts for crucial applications.

 

[goofy]

Thank you. I've gone to the "dark side" of no longer trusting after-market parts for crucial applications.

more like ascension to "enlightenment"

 

[brages]

No

Sounds like something someone with a low blade count would say

 

[researcher]

Thank you. I've gone to the "dark side" of no longer trusting after-market parts for crucial applications.

I agree with you.. The number of aftermarket parts that are supposed to be exact copies are some sort of interpration of the original design. By people who clearly do not understand geometry and trigonometry! I wouldn't doubt if the aftermarket company lowered the number of blades on the impeller just to save $0.05 in production.

Nope I don't trust the decisions for parts the aftermarket companies have made no matter the claim that they have "more advanced engineers" than the automakers engineers who actually designed the vehicle! They can either be reverse engineers copying what the original engineers designed or get a job designing the engines if they're THAT good.. which they are not.

 

[PandaBear]

What matter is the total power and torque required to pump how many GPM. You can design with more blade, less blade, curve blade, deeper blade, etc etc. They may be quieter or noisier or run slightly more or less efficient, but the engine would typically spec the right amount of GPM for the rpm it runs in. You can run a higher GPM pump and waste a bit of HP if you don't need it, or run a lower GPM than spec and risk overheating in corner cases (high altitude traffic jam in the heat storm), but as long as the pump meets the spec, it should be good enough, just may not be the quietest.