Cause of Purolator Media Tears

[slalom44]

I have a theory why so many Purolator filters are tearing: The bypass valve has a very small spring which does not allow it to open up very far during cold starts. This cold winter we just had meant that almost all oil was flowing through the bypass valve at startup. If all the oil can't get through that small opening, then it's going to tear the media. Here's my rationale:

I cut open the PureOne filter on my wife's car last weekend (no filter tears) and tried to open up the bypass valve. It barely opened, no matter how hard I pressed it. Compared to other bypass valves I have seen on other filters, the PureOne valve has a very short range to open. This can be explained by the shape of the bypass valve spring: (photo borrowed from 2010_FX4)

Unlike a coil spring used on some other filters or a large flat spring on others, this has a tiny spiral-shaped spring. Sure, it will open up at the right pressure, but its range of motion is quite small due to the size of the spring.

Here is a photo from ten years ago on a failed SuperTech ST3614 filter I had with the old clicker-type bypass valve:

Look similar? (I know, bad picture) I had two of these SuperTech filters that failed back-to-back. A few months later, Champ Labs discontinued making those filters with the clicker-type bypass valves. I never could figure out how they could possibly open up. I guess Champ Labs eventually came to the same conclusion.

If my hunch is correct, we will likely see less failures in the future because the Polar Vortex is behind us. But some people like revving their engines when they start their cars, so we may still see more failures until Purolator changes this design.

 

[crazyoildude]

I personally don't know why they tear and personally dont care because a lot of people in the business including me stopped using them for that reason. But you may be on to something i don't know why the cold winters had anything to do with it there are much colder places than nj and we have the tear problem also.
Stay away from them and you won't have anything to worry about unless you buy a used car that used them

 

[Brybo86]

Any people from Florida or Texas reporting tears?

 

[sprite1741]

My PL-14006 tore and it didn't have one of those springs. It's a GM LS4 V8 and the bypass is internal to the engine, not the filter.

 

[nobb]

The Bosch Premium and Purolator Classics that I noticed tears on did not have that spring design and some were even used in the summer. The media is just poorly engineered.

 

[sicko]

To my knowledge the bypass design has been around since well before the media tear issues started showing up.

 

[CarbonSteel]

Originally Posted By: Brybo86
Any people from Florida or Texas reporting tears?

Yes... 3 Tears in P1! I do not think it is the bypass. I think it is the wide gap in media near the seam that allows too much flex.

 

[tony1679]

Originally Posted By: sprite1741
My PL-14006 tore and it didn't have one of those springs. It's a GM LS4 V8 and the bypass is internal to the engine, not the filter.

I also have seen tears on my LS4 filters (mine were PL12222) although the 2007+ models have the filter bypass. One was winter/spring, one late spring/summer (never below 50*F). I adopted a "two strikes, you're out" policy on my family fleet. I have also happily switched to Wix.

 

[slalom44]

Thanks, all that have responded. I thought I was on to something when I saw how little that bypass valve opens up. at a flow rate of 10 gallons per minute or more (6 gpm at idle) for a typical engine, that puts a lot of stress on the media.

 

[demarpaint]

Originally Posted By: sicko
To my knowledge the bypass design has been around since well before the media tear issues started showing up.


Exactly.

 

[Hokiefyd]

Originally Posted By: slalom44
Thanks, all that have responded. I thought I was on to something when I saw how little that bypass valve opens up. at a flow rate of 10 gallons per minute or more (6 gpm at idle) for a typical engine, that puts a lot of stress on the media.


You still may be on to something. Just because a design has been around for a while...that doesn't mean that recent manufacture can't be slightly off or too tight or whatever.

I think the same argument can be made about the media spacing...filters have had widely-spaced media for some time, including Purolators, but we haven't seen a rash of tears like we have recently. Just as with the bypass spring: the media design has been around for a while, but that doesn't mean that recent manufacture can't be slightly off or too widely-spaced or whatever.

For what it's worth, I live where it's pretty warm, even during the winter, and I've never had a Purolator with a tear. I've cut open most filters I've used, but have only started posting pictures of my non-failed ones recently. I'll admit that most of my stash was built-up a number of years ago; most of the failures seem to be happening on more recently produced filters.

 

[Sayjac]

Originally Posted By: slalom44
..Look similar? (I know, bad picture) I had two of these SuperTech filters that failed back-to-back. A few months later, Champ Labs discontinued making those filters with the clicker-type bypass valves. I never could figure out how they could possibly open up. I guess Champ Labs eventually came to the same conclusion.....

I don't know about that. Look at the Champ made STP S2808 and it still uses the 'clicker type' (or so I've been led to believe that's the name) bypass as shown in the links below. In the first, the one I used, it 'appeared to' work fine. But in the second as posted recently, the Deere filter, there is a tear as you noted. But I agree with you on one thing, no idea, how that odd design is supposed function as a bypass.

So it appears that Champ is still using the design at least in some of their lower/lowest tier filters. Those that haven't gone ecore, which is what your pic of the ST3614 equivalents like STP, Fram Core and Firestone quick lube are now.

1.) STP S2808/8k oci w/ curious bypass design
2.) Purolator isn't the only filter failing

As for the flat spring design, I've used and posted pics of many PL14610's, which use the flat spring design, and 'never' had a tear. Using one now currently going on 6500 mi. oci. Granted, some of my stash is/was older, but so are some of the noted tears.

Suppose it could be 'a factor' but imo there's not enough information available to confirm one way or the other.

 

[route66mike]

I'd put the blame on the cause of Purolator tears on natural variability of wood pulp material properties from year to year. As we all know, wood isn't entirely consistent, and the cellulose media thickness that was strong enough in 2008 might not be in 2014. Density of each fiber.

 

[ZeeOSix]

Originally Posted By: slalom44
I have a theory why so many Purolator filters are tearing: The bypass valve has a very small spring which does not allow it to open up very far during cold starts. This cold winter we just had meant that almost all oil was flowing through the bypass valve at startup. If all the oil can't get through that small opening, then it's going to tear the media. Here's my rationale:

I cut open the PureOne filter on my wife's car last weekend (no filter tears) and tried to open up the bypass valve. It barely opened, no matter how hard I pressed it. Compared to other bypass valves I have seen on other filters, the PureOne valve has a very short range to open. This can be explained by the shape of the bypass valve spring: (photo borrowed from 2010_FX4)


Purolator has been using that flat spiral spring design on the bypass valve for years. Why would it all of a sudden be causing media tears? IMO, it's not the bypass spring design that is the problem with tearing media.

This bypass design has been discussed many times. Yes, it feels "stiff", but if you do the calculation to see how much force is required to make it crack open, then you'd see that it indeed does open in the PSI range that Purolator specifies for this bypass valve (14~18 PSI for a 14610).

Keep in mind that media must be able to at least take the same delta-p that a bypass valve is set to open at - that is a basic design criteria for an oil filter. As others have mentioned, IMO it's a combo of large pleat spacing, large V-spread spacing and weak media all adding up to the media tearing due to forces impinged on the pleats as oil flows through the filter.

 

[ZeeOSix]

Originally Posted By: slalom44
Thanks, all that have responded. I thought I was on to something when I saw how little that bypass valve opens up. at a flow rate of 10 gallons per minute or more (6 gpm at idle) for a typical engine, that puts a lot of stress on the media.


I doubt any engine puts out 6 GPM at idle. Not many will put out over 10 GPM at near red line.

There really isn't much delta-p across an oil filter ... see link below. At 12 GPM of hot oil, there is only 5 PSI delta-p. As said above, if the bypass valve works correctly, the most delta-p across the media would be whatever the bypass valve allows, which could be a 14~18 PSI delta-p in the case of the 14610 ( PL14610 Specs ) if some guy fired up his car at -10 F and revved the engine pretty high before the oil warmed up much.

Link: PureOne Flow vs Delta-P Data

 

[route66mike]

I've never seen any delta pressure data for cold oil. Once can assume its above bypass and guess that happens at 25 degF.

Is there any engineering equation that estimates what a cold viscosity delta-p would be, given a warm viscosity's delta-p?

 

[CarbonSteel]

Originally Posted By: route66mike
I'd put the blame on the cause of Purolator tears on natural variability of wood pulp material properties from year to year. As we all know, wood isn't entirely consistent, and the cellulose media thickness that was strong enough in 2008 might not be in 2014. Density of each fiber.

That or Purolator changed the spec by reducing the thickness in an effort to cut costs...

 

[Sayjac]

Quote:
....That or Purolator changed the spec by reducing the thickness in an effort to cut costs...

Well that's one conspiracy theory. Check back when you can prove it.

 

[route66mike]

Originally Posted By: sayjac
Quote:
....That or Purolator changed the spec by reducing the thickness in an effort to cut costs...

Well that's one conspiracy theory. Check back when you can prove it.


Thats not a "conspiracy". Speculation only. Don't react like a jerk.

 

[ZeeOSix]

Originally Posted By: route66mike
I've never seen any delta pressure data for cold oil. Once can assume its above bypass and guess that happens at 25 degF.

Is there any engineering equation that estimates what a cold viscosity delta-p would be, given a warm viscosity's delta-p?


In that link I gave 5 posts above, there is a graph in that thread that shows delta-p across various filers with cold/thick oil.

Keep in mind that when the oil is cold & thick that the oil pump will also go into pressure relief much easier and will therefore send much less GPM output to the filter/engine circuit. This means there will also be less oil volume going through the oil filter when the oil is cold & thick, which does help keep the delta-p across the filter down.

Even though the flow is reduced, the filter will most likely go into bypass, so again the most delta-p that would ever be across a filter's media is whatever max the filter's bypass valve is set to.