Dunno - but the AJ6 engine was designed in Browns Lane, not in Stuttgart so maybe it doesn’t have one - unless the oil filter itself caters for a potential blockage. But a Jaguar owner would surely NEVER delay his oil changes to allow crud to build up enough to block the filter? 
I’ll send pictures later of the units with this by pass valve and perhaps you can decide whether
it would function as a filter by pass due to blockage.
Tons of knowledge and a sense of humor. Thanks againJust Google ‘oil filter bypass’ - very informative!
The first pic is what it looks like at the block.
Second is the by pass housing side that mates to the block.
Third is the opposite side of the by pass housing, which is the mating surface for the filter housing.
fourth obviously the filter housing.
Hope they’re clear enough to show a bit of the internals.
The first pic is what it looks like at the block.
Second is the by pass housing side that mates to the block.
Third is the opposite side of the by pass housing, which is the mating surface for the filter housing.
fourth obviously the filter housing.
Hope they’re clear enough to show a bit of the internals.
Wasn’t sure how to post these pics with our discussion so I sent them to Bryan also.
Feel free to post them if your able to.
Thanks
Hi,
When searching for a replacement oil filter you will find lots that are described as a match for an XJ40, however, if you read the different manufacturers specifications you will see that some are described as having an internal relief valve and others are not.
I always use a genuine Jaguar brand marked replacement for peace of mind.
I think we have the answer. Thanks to all participants.So yeah a quality filter (I’ll be using a Mann filter) and going with what Bryan’s manual
suggests is acceptable. Thanks to all.
Mann filter over here too 