Ok, I went off on my own and did some research.
I needed a coolant pump for my 'o2 3.0.
Prices in town ranged from 160 to 190 for it.
When comparing pumps, I found no matching numbers
from Ford or Mazda to Jaguar parts.
But I noticed each and every gasket,
for each make was the same part number.

So I found a store with the Jag and Mazda pumps in stock
so I could compare them in person.
(Funny thing, the expensive Jag part, new in box had a broken impeller)
But they are almost identical, comparing the specs, exact.
SO I got the carquest T1159 for $49.99 instead of the T1179 for $191.99
and have it on my car and it is working.

Am I gonna pay for this? Anyone know?
Even the pulley was the same.

I could of even paid less once I made the match.

 

innzane, this is a very subjective thing to ask. The big question is whether they are truely exactly the same. In the case of a centrifugal pump (ie, one that spins the water to the outside to make it move the water), the clearance between the impeller and the pump casing can be very critical. Get too much gap and the pump will not be able to generate enough pressure to properly push the coolant around the system.

Doing some research, from what I can tell, the two pumps that you list have the same "interchange number". So, this should mean that they are identical in every way. So, you should be good.

Now, not to make you slap your head, but e-bay had a GMB water pump for your X-type for $25.00 delivered to your house. C'est la vie. How fast do you need the water pump.

 

Yeah, I saw that. My 9 to 5 is selling on ebay so I am always there.
But at $15 a bottle for coolant, I had to do the fix now.
It was dripping out fast and the Jag is my only ride.
Looking at the GMB, I could not confirm it was a complete pump with imp and pulley.

Both pumps I looked at in the store had the same impeller,
low quality black plastic, not the hard white plastic.
In reality, the cheap pump cost more to produce, it had
a BB plug where the $191 did not.