I'm servicing and restoring my XJS V12, learning as I go along (small jobs first then bigger ones as I get more confident...). A fantastic engine and mostly making sense to me so far. However I'm working in the engine bay and not sure what this part is or what it does - very grateful to anyone who can enlighten me. Thanks, Andy.

 

That is the filter that goes at the end of the vent line from the distributer cap. It mounts under the l/s strut brace forward of the master cylinder.

 

By the way, it's exactly like the fuel filter used on a 60's VW beetle. Looks exactly the same and may be cheaper if it does not come in a bag or box that says Jaguar on it. Most auto parts stores have them.

 

Ahh, that makes sense. Many thanks guys.