Denso style oil filters - how do they avoid bypass?

[dwasifar]

Denso makes OEM cartridge type filters for Toyota. They also make spin-on filters for Toyota and other brands, but they are basically a cartridge style filter inside a can:

Those blue arrows were drawn by me, and what I want to know is, why does this design work? Without a glued end cap, why doesn't oil just push through the gaps where I drew the arrows, flow into the center tube, and bypass filtration entirely? The Denso cartridge element design is basically the same, just inside a housing rather than a can, and so I have the same question there.

Other brands of cartridge have the ends completely glued up, like this Mann:

Why doesn't Denso need to do that?

 

[Jetronic]

pressure closes the folds

 

[JavierH19]

It does. I went to Walmart with a little paperclip since I was curious and was able to shove it through the hole though it had some resistance since it's folded tight however only so much can flow through them before the pressure builds and it then becomes easier to flow through the media. These have a 50% efficiency which sounds right as a cheap orange can fram with equally cheap media but with sealed caps can do 95-96% instead. But the filter is still going to catch some stuff just not as much but many toyotas seemingly run forever with these cans on them but I still wouldn't use one. The oil filter adapter likely has the bypass built into it since it is better that way.

 

[zfasts03]

I think the pleats are glued on the inside, maybe the one was defective?

 

[Glenda W.]

I believe the raised center tube seals into the ADBV. Pleats should be sealed at the ends but as @JavierH19 mentioned QC is lacking.

 

[dwasifar]

"Sealed at the ends" meaning the spots I drew arrows?

 

[Gravity_Wolves]

"Sealed at the ends" meaning the spots I drew arrows?

Glued

 

[Glenda W.]

"Sealed at the ends" meaning the spots I drew arrows?

Yes either glued or bonded.

 

[Fair enough]

There is a band of glue on each end sealing the pleats. No excess glue on these like other filters. The center tube isn’t glued. The Denso aftermarket made in China isn’t the same.
Best to buy and cut, then there is no speculation.
Here is a guy who cuts open filters so we don’t have to. Not that impressive, made in C and the adbv is not silicone.

 

[ZeeOSix]

The end of each pleat is glued to seal the gap, were the blue arrows point. Now if every single pleat end is sealed 100% is another thing. If any are not totally sealed by the glue, then it could leak dirty oil.

 

[sxg6]

I have a yzzn1 I cut open for part of a discussion on rav4world a week or two ago. I cut out part of the media and I can confirm they are glued shut. I couldn’t stick anything up there like a paper clip, and when I pulled the pleat open you can tell it was glued. It’s roughly glued where the red arrow is, where the first line on the media is.

(Edit: I attached a second pic showing how far up a paper clip goes for me, where the green tape starts, about 2mm)

 

[Sayjac]

Denso makes OEM cartridge type filters for Toyota. They also make spin-on filters for Toyota and other brands, but they are basically a cartridge style filter inside a can:

View attachment 282804

That's true, and yes pleats are sealed at the ends. What's interesting about the pic/illustration you posted is it's from Denso First Time Fit (FTF) site which 'I've' never seen use the Toyota Thai Denso OEM no endcap design. Always metal caps and continue that with now China made black can FTF. That site also continues to maintain the "Denso FTF'" uses silicone adbv, also inaccurate.

 

[cheesepuffs2]

There is a band of glue on each end sealing the pleats. No excess glue on these like other filters. The center tube isn’t glued. The Denso aftermarket made in China isn’t the same.
Best to buy and cut, then there is no speculation.
Here is a guy who cuts open filters so we don’t have to. Not that impressive, made in C and the adbv is not silicone.

I think these Densos are actually quite impressive considering the decline in filter quality that we've seen across the entire industry. That fact that the pleats are straight, no media tears, metal end-caps that didn't come unglued, and the ADBV sealing up well, all sound great to me.

 

[RallyXaDSM]

I think these Densos are actually quite impressive considering the decline in filter quality that we've seen across the entire industry. That fact that the pleats are straight, no media tears, metal end-caps that didn't come unglued, and the ADBV sealing up well, all sound great to me.

Their QA seems to be slipping too, unfortunately. The two that I've opened recently looked fine, but this guy had nearly a whole box of them from the dealership be defective

https://bobistheoilguy.com/forums/t...k-mi-30-minutes-of-bg-epr.374886/post-7242307

 

[cheesepuffs2]

Their QA seems to be slipping too, unfortunately. The two that I've opened recently looked fine, but this guy had nearly a whole box of them from the dealership be defective

https://bobistheoilguy.com/forums/t...k-mi-30-minutes-of-bg-epr.374886/post-7242307

That's disappointing to see, but the actual Toyota branded filters are made in Thailand and the Denso aftermarket filters like in the video above are made in China, and there have been postings here before where Denso customer service has replied that the OEM filters have different efficiency too. So this may not affect the aftermarket Densos. Not sure.

 

[CR94]

In an Advance store, I found Purolator cartridge filters constructed superficially similar to corresponding Toyota cartridges , except that the ends of the pleats were evidently not sealed. Ugh!

 

[cheesepuffs2]

In an Advance store, I found Purolator cartridge filters constructed superficially similar to corresponding Toyota cartridges , except that the ends of the pleats were evidently not sealed. Ugh!

Purolator, in my opinion, has been a brand to avoid ever since the "Tearolator" days around ten years ago.

 

[53' Stude]

Denso makes OEM cartridge type filters for Toyota. They also make spin-on filters for Toyota and other brands, but they are basically a cartridge style filter inside a can:

View attachment 282804

Those blue arrows were drawn by me, and what I want to know is, why does this design work? Without a glued end cap, why doesn't oil just push through the gaps where I drew the arrows, flow into the center tube, and bypass filtration entirely? The Denso cartridge element design is basically the same, just inside a housing rather than a can, and so I have the same question there.

Other brands of cartridge have the ends completely glued up, like this Mann:

View attachment 282805

Why doesn't Denso need to do that?

Dunno, don’t care. My Toyota filters that cross to 3614, are working great on my ole Whitney 02’ Dakota truck. I’ll keep using these

 

[ZeeOSix]

In an Advance store, I found Purolator cartridge filters constructed superficially similar to corresponding Toyota cartridges , except that the ends of the pleats were evidently not sealed. Ugh!

How could you tell? The glue might have been pretty far down from the pleat end, and you'd have to stick something down the pleat end to tell. Maybe it was a manufacturing defect? No filter engineer is going to design a filter like that and not seal the pleat ends ... if so, they shouldn't let the summer hires design oil filters, lol.

 

[Sayjac]

In an Advance store, I found Purolator cartridge filters constructed superficially similar to corresponding Toyota cartridges , except that the ends of the pleats were evidently not sealed. Ugh!

Sure would like to see proof of that claim. I realize Purolator generally poorly regarded on this subforum, but them purposely manufacturing cartridge pleating ends open to oil bypass on a whole other level, 'imo'.