The NAPA Gold 1515 has been the go to filter on my '96 4.0 for a couple years now. It's a WIX 51515. Do you mean it's hitting somewhere?

 

Yeah I guess, the oil filter adapter diameter is smaller than the 1515 or 51515 diameters. I'll measure them both later.

 

The sealing surface is correct though...............

 

It really doesn't matter as long as the gasket is the right diameter and it has a 3/4-16 thread. Even a dinky 51056 will work. I tried one on my 2000 when I was screwing around trying to eliminate the adapter. The oil flow rate is the same and the bypass pressure is the same. It just gets dirty faster. BTW, it didn't change the idle pressure one bit either.

 

They work just fine on my 94 and 97 XJs, and my 02 WJ. I'm pretty sure it's exactly the same on all years.

 

Maybe you don't have a Unicorn then.

 

Here are pictures of the old filter vs the 51515... big difference

 

Measure the round rubber seal as a comparison.

 

Yes it is! Any identifying info on your old filter? Did you try the Wix on your XJ?
I spent a lot of time checking the specs on various brands of filters for the 4.0. O.D. on all I checked were 3.66" to just over 3.7".

 

Wix website specs a 51085 for that engine.

 

25 posts dealing with something we all know works just fine?
I want a raise!!!

 

Checks in the mail.

Along with a BUNCH of others:https://www.oilfilter-crossreference...vert/Wix/51085

 

Wix website specs a 51085 for that engine. It's 3.660 diameter. As I've said before, as long as the thread is right and it doesn't leak, you're good to go. The only specific differences are bypass pressure.

 

If that old filter sealed it wasn't by much.

 

Is that check for double what I make now??