New NAPA ProSelect 21521 Cut Open

[river_rat]

This is a NAPA ProSelect 21521 that is used on the 1972 and later Volkswagen vans, 411s and 412s.
(But don’t take my word for it—check the part numbers.)
Anyway, I use this filter and wanted to cut open one of the new bypass style ProSelects. So far this filter hasn’t gone up like the WIX 51521, and I only paid $3.04 for it. This one has the looks-like-nitrile combination bypass and anti-drainback valve instead of the steel spring assembly it used to have. This new bypass design is similar in function to the E-core filters.

I think it’s a pretty good filter for $3-ish, but this ProSelect media is still thinner and weaker than the WIX/NAPA Gold…and really appears much more porous than the costlier Wix/NAPA Gold. You can see a fair amount of light coming through the “pinholes” in the media on this one.

50 X magnification:

 

[ZeeOSix]

So how is this funky combo valve supposed to work as a bypass valve? In other words, what happens with it when the filter goes into bypass mode?

Can't really get a bearing on how it really functions from the photos.

 

[river_rat]

Looks like the ecore deal, but only one set of holes, so I guess if pressure gets too high across the element, it flexes open and lets oil dump into the thread end of the center tube.
There is a lot of "rubber" showing in the center tube when you look into the middle hole. So instead of oil going to another set of holes that connect to the center tube, ala ecore, it must just open directly into the center tube.

 

[Sayjac]

Yep, got one of them there grommet* lookin combo valve thingies.

Thanks for the pics.

* Credit to the ARCO for the NPS combo valve name.

 

[river_rat]

I wonder how they work when it's really cold out? Of course then the oil is thicker, but still. I like the steel spring better.

 

[ZeeOSix]

Originally Posted By: river_rat
I like the steel spring better.


Yea, me too. Hard to have a good old metal spring screw up on ya.

 

[Sayjac]

Originally Posted By: river_rat
I wonder how they work when it's really cold out?...I like the steel spring better.
That's a good question. Seems odd to use such a good coil spring design with a nitrile combo valve. JMO.

 

[river_rat]

I think I'd feel better if it were silicone, but I have no proof silicone works better in the cold...it lasts longer without hardening. Pretty critical application. The bypass positively must work flawlessly every time in all weather or you are in trouble.
Hopefully it was thoroughly tested and probably was.

 

[motorguy222]

I recently wrote WIX about a by-pass valve in a different filter,it didnt seem to have one.I was told that it is this type of valve and they called it an "up front by-pass valve".

 

[ZeeOSix]

Originally Posted By: motorguy222
I recently wrote WIX about a by-pass valve in a different filter,it didnt seem to have one.I was told that it is this type of valve and they called it an "up front by-pass valve".


A lot of GM applications do not have a bypass valve in the filter because there is a filter bypass valve built into the engine block near where the filter mounts to the engine.

 

[river_rat]

^^^I wish all engines had that feature.^^^

 

[motorguy222]

Originally Posted By: ZeeOSix
Originally Posted By: motorguy222
I recently wrote WIX about a by-pass valve in a different filter,it didnt seem to have one.I was told that it is this type of valve and they called it an "up front by-pass valve".


A lot of GM applications do not have a bypass valve in the filter because there is a filter bypass valve built into the engine block near where the filter mounts to the engine.


Yeah,GM has the built in valve but the filter I was asking about is for a Dodge and does have a bypass according to WIX.It is the new grommet type that sits in the base,just like in the pic.

 

[Drew99GT]

https://bobistheoilguy.com/forums/posts/1004819/

Scroll through that thread; I took some pics and tried to describe how this combo valve thingy works. After looking at it more thoroughly, I think it's actually not a bad design.

 

[ZeeOSix]

Aaaaah ... the new WIX "combo valve". Not sure I'm really feelin' it in the "like" department.

 

[river_rat]

Originally Posted By: ZeeOSix
Aaaaah ... the new WIX "combo valve". Not sure I'm really feelin' it in the "like" department.

 

[Virtuoso]

With Wix and Champ using combo-valves now, perhaps it's not such a bad idea after-all.

 

[river_rat]

Well, It is cheaper than the metal bypass, and I hope we still have a choice, but they probably tested them well...at least WIX probably did. As long as it works reliably, that's the main thing.
Overall, I think for $3.04 the ProSelect is OK. I wish the media was as tough and dense as the Napa Gold/Wix, but they got to cut corners somewhere.

A ProSelect

A WIX

 

[river_rat]

What the heck, here's some more:

A K&N

A Purolator Classic:

These 4 are all taken at very close to the same distance.

 

[Drew99GT]

Thanks river rat!

 

[river_rat]