I Have searched this forum for the OEM plugs in MY 2001 S Type 4L and have seen so many plugs recommended that now I am totally confused. Can someone tell me what the original plugs were installed at the factory. I know I can pull one out but I would like to have the new plugs in hand before I start working on the Jag.
Thanks
Howard

 

Looks like AJ84575 (iridium) which are NGK IFR5N10

Do not add antiseize/etc as they are already coated and be wary of touching the central electrode as they are very delicate.

They tend to be easier to get out with warm (or hot) engine.

 

However... - if you want to go for something, which is simply better than OE (this did not exist in 2002!), then go for Denso Iridium TT spark plugs.
Check the internet, what TT is (twin tip). I use them in all my S-Types and X-Types and X308.
The correct spark plugs for your model (I checked the Denso catalogue) are: Denso Iridium TT called "IK16TT"

 

Thank you. I really appreciate this information.

 

Thank you, I will check them out.