Getting ready to do spark plugs on my 03 X-type 2.5. Iv read all the instruction and i know how much of a B#$h its going to be to get the intake off...

So all i want to know is what type of plug to use? Platinum vs dual electrode vs iridium

Bosch vs Autolite vs NGK

Any thoughts?

 

Not that hard to take the intake up a couple inches(you really don't need to completely remove it). Plugs are like women, everyone has their preferences and there usually isn't much behind why their choice is the best. I've used NGKs for years as they have never given me a problem in any regard. With a plug that is going to be in there for a long period of time you want to get something that will last. I replaced mine at 100k and they were shot. Car ran fine, mileage didn't increase with the tune up noticably but they were very worn. Used NGK Iridiums and don't plan on changing plugs again unless I'm there for another reason. I have never seen any added benefits to dual electrodes or other "latest and greatest" in plug tech.

 

After doing some research I answered my own question. But of all you guys....

If you have the 2.5 motor your limited on what you can use. its pretty much Autolite or NGK

Autolite iridium is gonna be the best
Part Number:
XP103
Then there alway is going with OEM, if you wana pay 3times as much for them.

There is also a platinum option, but your Jag deserves the best.

 

I have tried the "multi point" spark plugs in a modern engine. All that it gained me was a lighter wallet. No change in performance, no change in mileage.

Now, I will tell you to go with a double platinum plug (ie, both the center electrode and the arm coming over the top are made of platinum). These plugs are worth the money as the platinum will resist wear better than a conventional plug or even a standard "platinum" plug (only has platinum on 1 of the electrodes). Now, the iridium plugs will wear a little better than the platinum plugs, but after 100K miles, the difference is not going to be significant. So, whether you use a double platinum or an iridium plug, that is up to you. As for brand, as long as you stick with a major name brand, you should be good. I have heard all the stories of "this brand is far superior to this other brand" yet the next guy will say exactly the opposite. So, it is somewhat of a gamble as to whether you got the plugs made on the monday after a long weekend or the ones made on Wednesday.

 

Nor will any plug do such a thing. The mixture ignites at the least sign of an adequate spark. A 'hotter' spark or multiple sparks can't and won't cause more energy to be released. Spark plugs are marketing spin at it's best, uhhh worst.

 

the factory plug lasted 100000 miles on my car, and still looked fine when I changed them. Never a missfire, no carbon build up, no run on, zero running issues.

I cant for the life of me see ANY reason to use anything different. I mean there is nothing wrong with them. I got the replacements at a ford dealer, 1/3 the price of the Jag dealer for the same plug.

 

Get the part number and look it up on Google, betcha Amazon has them even cheaper.

 

My 03 X has 24078 miles on it. The gas mileage to me is below par. 20 to 21 mpg on highway and 19 mpg. Also I notice a lot of black carbon on both tailpipes and stuck my finger inside the pipe and there is a lot of carbon buildup. Which usually, to me, mean one of two things a rich mixture or the plugs are on there way out. I have most of the service records from when the car was new all work was done by a Jaguar dealer. There is nothing saying the plugs were ever changed. Think this is the problem and oddly the owners manual says nothing about sparkplugs in it. Which is probably the first car I've owned that did not address sparkplugs or what type to use in the owners manual. I called the Jaguar dealer and the service guy said you will have to bring the car in so we can check what plug is has. BS they just want me to have them install a new set and charge me too much money. I did asked for a quote for the job, again you have to bring the car in. Their 28 miles away and being handicapped I can't drive that far both ways. They said they would pick it up and return it for 100 bucks. When I had a Benz they did this for nothing.

 

Adam, I wish you lived a bit closer to me. I would tell you to come on over and we would get you taken care of. Changing plugs isn't that hard, but based on your situation, I understand why you can't. Maybe one of the members in your area will be willing to give you a hand.

As for plugs, you will want to find either Motorcraft SP459, Bosch 4005, or the Denso 4511. These are all plugs that will work in your car. It is just a matter of what you hav e a preference for. Hopefully this will get you going in the right direction.

 

plugs are not due until 100k miles !!! there of course is no indication of them being changed, they are not due yet. It is in the service booklet, not the owners handbook.

with an '03 and only 24k miles, you dont drive very much or very far. that means the car does not do a lot of miles when it it fully heated up. If you cant drive 28 miles, then I dont think you shoul complain about gas mileage.

The car will never get good mileage with short trips, and for sure it will spend more time doing the "warm up cycle" which is richer running. This will give black tail pipes. There is no reason to suspect there is anything wrong with your car. There is no reason to belive there is a plug problem the way I see it. Find someone to take the car for a one hour highway drive... "burn the carbon out" that is the oldest line in the book!

If the service guy at the dealer cant tell what plugs you have without looking at the car.. he is a 'tard... sheesh what a bozo. tell him to go ask the parts guy to look it up.

 

I still 'blast' out the carbon at least one day a week on the highway. It is amazing every time I do it how much carbon comes out of the tailpipe.

I just pin it in 2nd until just about redline and then take my foot off the gas and coast it back down, usually somewhere around 3000-4000 RPM I notice carbon coming out of the tailpipe.

 

Running WOT (wide open throttle) will put the mixture super rich, to avoid problems... that black smoke is NEW carbon you are adding to the system, not blowing out old carbon. You need high rpm, and relatively light loads. Not even sure if it helps anyway, but it is fun.

the point was more that slow, short trips wil also be running rich...

 

I drive in traffic about 25 miles each way on my commute. Average speed....26 MPH. I know it carbons up, you feel the slight hesitation on the pedal etc. There is one stretch where I am approaching the offramp on the home commute, I blast it up and then coast right off and to the stop sign, 1/4 mile maybe, then it's better after that. Short commutes are death to motors.

 

Adam,

Bad spark plugs will not cause the soot and poor mileage you mention. As mention previously, they either fire or they don't- there's no in between. If they don't fire this will be noticeable as a loss of power and possibly with a 'chugging' feeling from the engine. Your problems are elsewhere.

 

Interestingly my car runs very well and does not hesitate or idle rough or anything else that would indicate there is something not right with the engine. Only complain is fuel mileage, and as some have written this is caused by my driving. I don't drive a lot.

 

I replaced my orig spark plugs at 70k...still looked decent. The replacement was Champion Iridium's. I would caution on the factory torque spec for the plugs as I had a spark plug on the rear bank work loose and get blown out of the cyl head! This was an odd situation given it took place some 25k miles after my plug change.

The dealer wanted to take the entire engine out and send it to a third party machine shop to fix stripped threads in cyl head.

I declined and bought a Timesert kit (#4412E) for $185 and cut new threads myself and added a new solid insert in about 1.5 hours in my apartment parking lot. I re-torqued the all spark plugs to 15ft/lbs vs the factory 11 ft/lbs.

Been good since!

 

I have stripped many a thread over the years always rethreaded them myself. Oh the joy in doing that. The toughest one was a Mercedes Benz SLC 79 450 V8 the holes for the plugs were on an angle and rethreading them was a bear.

 

I am going to take some trips this week, as I own this to myself after the hospital stuff last Friday. I posted in off topic what the results were if anyone is interested.

I am leaving soon to NH about a 100 miles round trip, tomorrow we are supposed to get 4 to 8 inches of snow, ice and assorted weather. so I might not go again until later in the week.

 

Surprisingly enough this job on the Jag was not too bad. I coated the cutting tap with wheel bearing grease to trap the metal shavings which worked excellent. I then did 1/4 turns with the cutting tap till I had 2 full turns then backed it out, and wiped the metal shavings off and re-coated with fresh grease.

I used a high-temp, oil-resistant Loctite 266 on the outside of the solid threaded insert that screws into the head itself.

I could not believe the dealership wanted to yank my whole engine over some stripped threads! I suggested just to pull the back cyl head and they stated it would take 10 additional hours of labor vs pulling the whole engine.

There was no way I was going to spend 1/3 of the value of the car on a simple repair such as this. Bottom line was they did not want to be liable hence them using a 3rd party machine shop that never returned my calls or emails.

I wrote the dealership and explained what I did, the cost, and success I had and they stated that sometime the insert can come out with a spark plug change and that they wanted a permanent solution. I rebutted and said so a $3.00 insert comes out every 70-100k miles with a spark plug change (if it comes out at all!). So charging me $3500 is worth the savings of a a $3.00 item every 70k-100k miles. I don't think so.

 

I never had a problem with a thread coming out when I retreaded a spark plug thread. If it is done correctly it will last and it seems from your writing you did it correctly.