Greetings, My 03" XK8 is just about to hit 100K miles and I want to give her some TLC. The service book say to change the plugs at 100K miles but it doesn't say anything about the coils. As long as I'm in there does it makes sense to change them? Also, there is such a wide range in prices in the aftermarket ones and the OEM ones are stupid expensive. So, the question is do they need changing and am I better with 100K OEM coils or new aftermarket coils? I see new no name aftermarket set going for anywhere between $99 a set on Amazon, to $165 a set on eBay, to $300 plus for NGK on eBay. Any recommendations from experience would be greatly appreciated.

 

I wouldn’t fix an original part that’s working perfectly with a sub standard aftermarket part that certainly don’t have the quality reputation of the OEM’s.

if anything, buy a couple of the Denso coils
and keep them as spares. An OBD-II reader can pretty easily pinpoint a bad coil. And substitution with another cylinders coil can verify if you
have a bad one.

Z

PS for reference, my 2002 XKR is still running very well on the original coils at a mileage of 172,300.

I did change the original spark plugs at 159,000. Mainly because I was curious how they would look. They looked fine.

 

You might consider the OEM-quality coils from either NGK or Denso (NGK number U5082; Denso 673-9331, per my records). They are available from Rock Auto for about $35 - not much more than the no-name brands on eBay and a lot less then the Jaguar OEM. I would avoid the Chinese imitations and the auto parts store private-label brands. I was not as fortunate with my coils as member zray, as three of the originals failed within 100,000 - 110,000 miles, and finding the shorting culprits got to be time-consuming. Initially tried the "Duralast" coils from AutoZone. Two failed shortly after install, as did one of the warranty replacements (Neither "Durable" nor "Lasting", you might say). Then bought the NGK coils, as the Denso were not readily available at the time, and NGK bravely offered a three-year warranty. Been trouble-free to current 140,000 mileage. As you may know, Denso made the original OEM coils for the car and NGK, the spark plugs.

 

I had about 105k on my 03 XKR when I decided to replace the plugs and coils. I was getting what I felt was a subtle misfire upon startup that was not throwing a code. Figured it would be a good idea to just replace all of the coils and it was pretty inexpensive as I bought the ENA coils on Amazon and NGK Iridium on eBay. The car seemed to run a little more responsively after and the very subtle misfire sound was gone. Just my opinion but why not replace all of them as it is not very costly and certainly cannot hurt and also you do not have to do it again for another 100k.

 

most of the aftermarket coils are trash and will give you restricted performance and horrible shifting before they give up completely. the OE for the new style is unknown but if you order the airtex 5c1240 they will come stamped with ford., you can’t buy the old plastic tube coils made by denso anymore.

my coils are still going at 200k.

 

My car came w/ junk no name coils. One was bad, another questionable. Shop gave me a set of used OEM to test drive before the cost of replacing them. End of coil problems until #8 started misfiring then failed. I wanted to get a reasonable price branded coil so bought one NGK from Rock Auto to replace #8. No logo or label. Asked Rock to do an exchange. Done. Same problem so returned. Bought one Delphi (OEM spec BMW, etc) for $60. No logo but at least brand name is visible in the plastic. Several reviews mentioned different quality coils (for the same car) under the Delphi brand so maybe OEM quality, maybe not. Options seem to be 1) junk, 2) maybe better and 3) ridiculous price OEM. Plan to replace all since, right now, I've got used OEM w/ unknown mileage.

 

I’m buying a couple of NGK branded coils for my spare parts collection, as the original Denso coils are no longer available, afaik. I trust the NGK’s to be in the same league as the Denso’s until proved otherwise.

by the way I’m seeing a different part number for the earlier 4.0 XK’s vs the 4.2’s .

Anyone know if they are interchangeable ?

Z

 

Source on the NGK's? Price? Early 4.0 are 2 pin connectors. My 2000 is 4 pin.

 

Here is the link to the listing of NGK spark plugs I purchased for $80 with shipping included. Looks like there might be only one set left. Wasn't sure if you were looking for the plugs or coils:
https://www.ebay.com/itm/292000689351

 

Rockauto.com has them (the 4 pin type) for about $66 each

Buyer's Guide : NGK 48672 Ignition Coil

 

I ordered an NGK coil from Rock. Got one w/ no logo or name. Any pictures I've seen on line for an XK8 show a clearly visible name/part# in white on the top

 

Thanks. Rock's picture shows a coil with NGK name/part# clearly visible. Ordered 2x and got generic black/no name both times. Why I'm looking for another source. You had better luck?

 

Just ordered from StockWise Auto. $63 + tax.

 

ngk puts their name on anything they don’t manufacture coils for any oem


hitachi and denso do

 

I’ll probably follow your lead, but @ $14+ their shipping is certainly high to my locale.

it’s a shame RockAuto sent you those generic coils. Usually they are reliable.

Z

 

Good Morning. I decided to change all the coils when I do the plugs. Rockauto has both the Denso 6739331 and the NGK 48927 (shows U5082 on the photo) for about the same price.

I know Denso made the OEM coils but will the NGK give better performance with the new NGK Iridium plugs? Not sure which way to go.

 

Denso and NGK parts are of equal quality as long as they truly ARE Denso and NGK parts....

 

Good luck w/ Rock Auto. They usually do a great job.

 

that's a good price. Mine were $90 on Amazon.

Z

 

My apologies to anyone who relied on my advice regarding the quality of NGK-branded coils. Bought a set from Rock Auto in Feb, 2019. They came in NGK- printed boxes and had the NGK logo and part number stamped on them, so thought they were decent. One failed a month ago, just prior to the expiration of the three-year warranty and was promptly replaced by Rock Auto. A second one failed last night, fortunately, not far from my garage, and I limped home under "Restricted Performance". I replaced it with one of the original Densos I kept as spares. Now, I am thinking I will just leave it in the car, as probably no more trouble than trying to navigate the replacement coils market at this stage. Just travel with a replacement spare and a small metric socket set. Anyone have a new/better choice for coils? Good experience with the new Denso 673-9331 or later model ones?