# Oil Filter bypass valve psi.......does it matter?



## Spokerider (Jan 25, 2014)

I have a 1993 1.9TD AAZ engine. On it, I have a GReddy oil filter sandwich adapter........so I can run a remote air / oil cooler. 

The GReddy sandwich adapter will not allow the vw Mann oil filter to be used as it is too wide for the adapter. I can either use a GReddy filter or a WIX filter.......with a width of 2.685". 

My main concern with using the WIX filter is that the bypass valve is 8-11 psi. The Mann filter is 36 psi. VW specs indicate and oil filter of 2.50 BAR [ 36.25 psi ]. 

Exactly what is the significance of said bypass psi ratings? Will any damage or ill effects occur if I use this WIX filter? 

There are no other WIX filters that will fit the GReddy and have a higher bypass psi rating. The filter is normally meant for Toyota, GM's and Grand Vitara's, up to 2.4 liter.


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## BsickPassat (May 10, 2010)

When it opens "prematurely", it allows the oil to bypass the oil filter media, so... no filtration of the oil.


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## The Kilted Yaksman (Oct 31, 2000)

Looking at all of the filters that cross reference for that fitment it seems 17psi is about the highest bypass value that can be found. Personally, I would want to stick with something that matches the factory spec, and would either dump that oil cooler, or maybe fit a remote oil filter mount that would make using the correct filter possible.


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## draper (Oct 22, 2016)

Spokerider said:


> I have a 1993 1.9TD AAZ engine. On it, I have a GReddy oil filter sandwich adapter........so I can run a remote air / oil cooler.
> 
> The GReddy sandwich adapter will not allow the vw Mann oil filter to be used as it is too wide for the adapter. I can either use a GReddy filter or a WIX filter.......with a width of 2.685".
> 
> ...





BsickPassat said:


> When it opens "prematurely", it allows the oil to bypass the oil filter media, so... no filtration of the oil.


Yep! 

Less pressure bypass opening -> less filtration -> easy oil circulation on engine -> better lubrication (with dirtiest oil how as said) -> less high mileage reliability.

Better performance on racing engines!


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