FWIW, if you're doing the spark plugs, I think it's also worth taking the boots off the coil packs and cleaning the spring/coil and contact inside. Sometimes they'll get slightly corroded, or will (like mine) have what seems to be burnt up silicone paste residue on them.

 

@Johnken
So without knowing what plugs you used, you either had ones that where not long life or if you had the jaguar recommended one, you do have a serious issue with your engine.

For example, Denso has iridium sets, ranging from 20K to 100K, even NGK has some short life iridium plugs. These ones have the standard nickel electrodes (on the - side), and that erodes quickly. Here is a link with some info on Denso iridium plugs and there expected life:
https://www.denso.com/global/en/prod...ug/basic/life/

The Jaguar recommended one (NGK IFR-5N10) does have a platinum piece on the negative electrode, and that is what it gives its longevity. So if you had this one, at 60k to have that much damage done is a sure indicator something is very wrong that needs investigation (urgently I would say).

My best guess however is you have used a normal short life plug (i.e. a 20K or so), that would make most sense, but I would check it if I where you.

 

Ok i will check. Sure thought I installed Iridium but it was a while ago. Engine running fine.

Let me see if I can find the model info on the old plugs.

J

 

Avos,

Ok these are the guys I used. I could have posted my used plug, but that'd be redundant.

I've no clue why they wore like they did, but engine is running fine. Maybe its this brand / model that one should be wary of?

John

 

FWIW, I just looked it up. The worn plugs went in 6 yrs ago at 71,000 miles. So the photo i showed of the worn plug is 6 yrs old 65,000 miles.

John

 

The ones you show for sure do not have a platinum tip, so are not the long life ones.

Here is some info from NGK:
https://www.ngk.com/how-long-do-ngk-iridium-plugs-last

These have an (avg) life expectancy of about 40-50K as they state, though driving conditions it could be longer. You may well gave fallen in the 40-50K range, so that could explain the wear.

Overall I don't think its a bad idea to check your plugs once in a while, but if you want long life best to use the NGK IFR-5N10 ones, these are for sure proven.

Good that you posted, am sure there are many who have bought shorter life iridium's thinking they would last.

 

Thanks my friend!!

John

 

If anyone does fit the NGK IFR-5N10 plugs they come with the correct gap 0.9-1.0 mm (0.035-0.039") already set - do not alter them to 0.052"

 

I am waiting on mine to arrive. Even if they already are correctly gapped, I will still be checking to make sure the factory didn’t make that mistake.

 

Be very careful when checking them as the Iridium centre wire electrode is easy to bend/damage/break.
See here for fitting advice: https://ngksparkplugs.com/en/resourc...ut-spark-plugs

 

Hmmm.... IMHO the platinum last longer and perform much better. But perhaps the discussion above regarding 'short life' vs 'long life' iridium plugs has some bearing on my bias. I didn't realize there were 'types' of iridium plugs. It seems a strange marketing strategy to advertise a longer life iridium plug only to then sort it into 'short life' vs 'long live' versions.

I'll have to see what I can learn about the iridium products now. Just what I need, another research project...

 

My comment was about the NGK IFR5N10 which last 100K miles (and don't look worn then). I don't know any platinum ones that last so long.

 

the only problem with NGK Iridium IX is the amount of fakes online and buying them at the parts store is $$

 

I suppose they last a long time so NGK charge more. Not a shock!