When I recently bought my 71 series 1 XJ6, the bloke told me it was missing a breather which now appears to have been capped.

Does anyone know what this part is and how easy it is to get a replacement.

The area of the engine is at the front (lights end) and appears to be next to the water pump on top of the engine.

 

I tried to get a copy of a picture and add here but I am not that IT savvy.

On the front of the cylinder head is a cover, about 4" diam, and there is a spigot pointing towards the air filter housing, and is about 1" in diam (memory here so watch out), and there is a hose and pipe arrangement that connects this spigot to the same sized spigot on the back of the factory air filter assembly.

When the air filter unit is substituted for "sports" air filters, there is generally no provision for this hose, so it is redirected to the lower part of the engine, and simply breathes to atmosphere, which the greenies hate.

It cannot be capped off, the engine MUST breath.

Try and photo the suspect earea and post here so we can try and sort what you got.

 

Maybe this will help:

 

That's the missing part. Will order one thanks