Oil Filter Help - 2002 Jeep KJ Liberty/Cherokee

Joined
Feb 12, 2022
Messages
9
Location
Italy
I'm looking for the right oil filter for my 2002 Jeep KJ (Liberty/Cherokee) 3.7L V6. Not sure when was the last time the oil and filter were changed (previous owner was family member who wasn't great with maintenance) so I'm guessing it's been longer than it should have.

The original oil filter part number is Mopar 04781452AA, which apparently has been replaced with 04781452BB and 04781452BF. I'm wondering if there's a way to know what the Bypass Relief Valve pressure is for these filters? I'm guessing it's 1 bar but I don't know.

There's several corresponding aftermarket filters, including Mann W 719/27 and Wix WL7077. Mann has a Bypass Relief Valve pressure of 1 bar but I can't find the pressure info for the WL7077, which is apparently a European part number (I'm in Italy and the car was purchased in Italy). On the Wix website it says WL7077 manufacturer is Wix Europe, and that the corresponding Wix part number is 51516XP and 51516 (which I believe have a lower Bypass Relief Valve pressure of 8-11 PSI). On another thread here someone said the American Wix 51315 crosses over to the WL7077 in Europe. The WL7077 is the only one I can get easily here in Europe but maybe the Mann is a better filter?

So I'm confused. First of all finding the original Mopar Filter in Italy is difficult and again I don't know what the bypass relief valve pressure is for it, not that it matters I suppose since it's the OEM filter. I don't know whether I should go for the OEM filter if I can find it off eBay or choose the Mann or Wix but again I don't know the valve pressure info for the Wix.

Another question is: if the oil and filter haven't been changed for a while and its a relatively old car, is a certain Bypass Relief Valve pressure better than another? My logic was that if its old oil and an old engine maybe it would be best to choose a filter that doesn't allow oil to bypass so that it gets filtered? Obviously it's an uninformed assumption on my part.

Any info on this would be really appreciated. Thank you and sorry for the long post.
 
Joined
Oct 23, 2005
Messages
7,998
We had almost that exact vehicle, used Wix 51315 filters, so in your situation I would go with the WL 7077 without hesitation.
 

MeepMeep

Thread starter
Joined
Feb 12, 2022
Messages
9
Location
Italy
Aren't there Chrysler dealers all over Italy or in neighboring countries? Or at least Fiat Lancia dealers that would have it or can order one? Rock Auto ships internationally.
There are, yes. I think the issue is the age of the car and the rarity of the 3.7L engine here, with the most common being either diesel or the 2.4L. Plus Jeeps really didn't start becoming popular here until relatively recently; you'll see lots of Renegades for example but not many of these. The dealerships just don't see many of them come through so support tends to lack a little. Another example of this is finding even a dealership with the old Chrysler DRBIII scanner to do enhanced diagnostics on the older Jeeps even though they're ODBII...it can be a pain if you have SRS or ABS issues as I've discovered.

I'll check out Rock Auto though, and actually you bring up a good point about going directly to Fiat, somehow...

Thanks
 

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
33,656
Location
PNW
The original oil filter part number is Mopar 04781452AA, which apparently has been replaced with 04781452BB and 04781452BF. I'm wondering if there's a way to know what the Bypass Relief Valve pressure is for these filters? I'm guessing it's 1 bar but I don't know.
If it's the filter specified by the manufacturer, then there is no need to worry about what the bypass valve setting is ... they've figured that out already.

Same goes with aftermarket oil filters that are specified for your vehicle ... the engineers have determined what the bypass valve setting should be.
 

MeepMeep

Thread starter
Joined
Feb 12, 2022
Messages
9
Location
Italy
We had almost that exact vehicle, used Wix 51315 filters, so in your situation I would go with the WL 7077 without hesitation.
Yeah I'm leaning towards the WL7077 as well. I just wanted to confirm the bypass relief valve pressure for it since on their site they list 51516 and 51516XP as the corresponding part number, not 51315. I sent Wix and Wix Europe an email to clarify, hopefully they respond...
 

MeepMeep

Thread starter
Joined
Feb 12, 2022
Messages
9
Location
Italy
If it's the filter specified by the manufacturer, then there is no need to worry about what the bypass valve setting is ... they've figured that out already.

Same goes with aftermarket oil filters that are specified for your vehicle ... the engineers have determined what the bypass valve setting should be.
Yeah that's what I was thinking too ultimately, I'm probably making too much out of this. Even though, the aftermarket filters specified for the car have differing bypass valve specs, from 0,5 bar to 1,6. That's why I was also wondering whether given the age of the engine and the fact that the oil at this point is pretty dirty, if it's better to choose something with a higher bypass valve setting to make sure unfiltered oil doesn't get through...but my logic could be totally flawed on this. Which is why I'm here : ) Thanks for your help.
 

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
33,656
Location
PNW
Yeah that's what I was thinking too ultimately, I'm probably making too much out of this. Even though, the aftermarket filters specified for the car have differing bypass valve specs, from 0,5 bar to 1,6. That's why I was also wondering whether given the age of the engine and the fact that the oil at this point is pretty dirty, if it's better to choose something with a higher bypass valve setting to make sure unfiltered oil doesn't get through...but my logic could be totally flawed on this. Which is why I'm here : ) Thanks for your help.
If you're going to try to "spec" you're own oil filter based on the bypass valve setting then you'll most likely be putting on a filter that is not specified for your vehicle. The bypass setting across 10 different brands of oil filters that are specified for your engine will most likely have some difference in bypass valve setting. That's because the bypass valve setting is not only based on the engine parameters like max oil pump flow and specified oil viscosity, but the setting is also based on the design of the oil filter. An oil filter that flows better (meaning less delta-p vs flow) will most likely have a slightly lower bypass setting.

The only time it makes sense to worry about the bypass valve setting is when someone want's to "oversize" the oil filter in the same brand filter. In that case, the oversized filter will most likely still have the same bypass valve setting (probably the exact same valve assembly), so again nothing to worry about. An oversized filter will help reduce bypass valve opening because it will have slightly less delta-p vs flow, and it will hold more debris which will delay the bypass valve opening events.

If you're worried about the oil filter loading up and going into bypass because the engine is dirty, then just do shorter oil and filter changes.
 

MeepMeep

Thread starter
Joined
Feb 12, 2022
Messages
9
Location
Italy
If you're going to try to "spec" you're own oil filter based on the bypass valve setting then you'll most likely be putting on a filter that is not specified for your vehicle. The bypass setting across 10 different brands of oil filters that are specified for your engine will most likely have some difference in bypass valve setting. That's because the bypass valve setting is not only based on the engine parameters like max oil pump flow and specified oil viscosity, but the setting is also based on the design of the oil filter. An oil filter that flows better (meaning less delta-p vs flow) will most likely have a slightly lower bypass setting.

The only time it makes sense to worry about the bypass valve setting is when someone want's to "oversize" the oil filter in the same brand filter. In that case, the oversized filter will most likely still have the same bypass valve setting (probably the exact same valve assembly), so again nothing to worry about. An oversized filter will help reduce bypass valve opening because it will have slightly less delta-p vs flow, and it will hold more debris which will delay the bypass valve opening events.

If you're worried about the oil filter loading up and going into bypass because the engine is dirty, then just do shorter oil and filter changes.
This makes sense. Thanks!
 
Top