What are the best spark plugs for the 4.2 xkr, is there a differnce in type for this engine and when should they be changed, iv'e 75,000 miles on clock.

 

I'd stick with the standard ones under European weather conditions. If they look alright, no carbon deposits, the temperature range is okay. Mine were changed after 60000 km.They still looked good, despite extensive high speed on the autobahn.

 

ok, have'nt even looked at them yet,,what would originals be, type/ part number, i was looking at NGK iridium IFR5N10 as one option.

 

Bosch
spark plugs
FR 7 KPP 33U

are used in Germany.

 

Alternative:

NGK 7866 for JAGUAR XKR 4.2

 

ok, what kind of air filters have you in are they k&n the red color

 

I don't recall the brand (Bosch I think) but Installed new iridiums at about the 50k mark. The old plugs were in great shape, and could have gone an easy 30K or more without worry. My primary reason for pulling the old plugs was to read the overall condition of the motor. As long as I was doing that, new ones went back in.

 

I used Bosch on the SV8 4.2 at 60k miles and they needed it. Every Jag cert tech I have spoken with on the subject has said 50-60k max to change.

 

I am sure that you will be able find plugs under many different brand names.

Select the brand that you like and just make sure that it is a proper fitment for your year, model, engine etc.

Here in the USA we have many brands to choose from.

My suggestion, pick a brand name plug, whether Bosch, NGK etc.

You might just want to select the same brand and part number that came with the Jaguar originally. That makes life real easy.

 

If you are pulling the plugs to look at them, why not just change them either way?

 

my local shop wud have to order in plugs, so i want a set in hand to change when taking old ones out. Don't know whats in a minute, so just want to know best type to get and proper ones, so many on web.

 

Standard plugs are Iridium (at least for the 4.2, according to the workshop manual) so I'd stick with those. The service schedule also says to change them every 100k miles. I've used NGK Iridium plugs in the past on other cars, never had an issue, if I was servicing my XKR myself and it was time for plugs then I'd probably get whatever NGK recommend.