How difficult is it to replace the spark plugs and ignition coils on a Jaguar S type 4.2 2003

 

Remember to post an introduction in the New Member Area.

Changing the coil units and spark plugs is not difficult, but due to the age of the vehicle, it may be also a good idea to replace the cam cover gaskets, spark plug boss seals and VVT seals as well.

 

Welcome to the forums John,

I've moved your question from General Tech Help to S-Type forum. Members here with the same model will be able to help.

Graham

 

Just a word to the wise: It is best to stick with OEM brand coil-packs, e.g., Denso, Dephi, NGK, etc. Bargain, no-name parts from eBay and the like have caused many, many headaches for forum members over the years.

 

The 4.2NA looks better plug access than the STR (where the rearmost are awkward). I found taking them out much easier with hot engine.

The correct plugs already have anti-seize on them and are pre-gapped. If you still wish to check the gap be very gentle as the electrode tip is meant to be very sharp and you could damage it thereby ruining the plug.

 

Apologies in advance, I am a noob, jumping in late to this thread.
My question: Since this is a Ford motor, I was wondering if I can use Motorcraft brand coil packs and plugs? Just in case: 2003 S-Type 3.0 V6 - BASE.

https://www.ebay.com/itm/32413701017...Bk9SR5Lc2-yOZQ

 

The 3.0 metal is Ford but the vital control system is Denso. You need the correct plugs & coils for that.

 

Does that mean not to purchase the Motorcraft coil&plug kit?
Apologies for being literal. I am a noob and still learning about my car.

Thanks again, folks!

 

If they match Jaguar's part # etc I guess they should be OK.

Keep any you take out in case they're better than what you buy...

 

Changing the coils and plugs on the NA 4.2 engine is pretty easy as long as you're careful. There's only a couple things you need to move out of the way. Make sure you carefully remove spark plugs so you don't break them. I use a big ratchet to remove and a smaller one to replace them with a little anti-seize on the plug. A little piece of rubber hose that fits pretty tightly on the plugs makes it easier to take them out when loose and put them in. Use proper torque settings. The car comes with Denso parts. I couldn't find any available and got NGK plugs and coils instead. They work great, You will notice an improvement with fresh ones right away. I found the best prices and service was from ordering from NGK directly. Don't get off brand ones, once in the good ones last a very long time.

 

I think the latest poster has the 3.0

In case anyone with a 4.2 is putting in NGK IFR5N10 plugs do NOT add anti-seize (NGK specifically state not to because they already have it).

 

Yes JagV8 is right. All us old guys still want to use anti-seize but if you read the plug manufacturer installation tips they all say no anti-seize as there is already a coating for this applied at the time of manufacture. With that said I have never had any problems with using a small amount of anti-seize. But it's not right!

I have attached a NGK bulletin on this subject and did learn that on plain steel spark plugs they still recommend using anti-seize. But they then state not many plugs are made that way anymore either.

Kinda like setting the plug gap. All plugs now come pre-gapped but I still check them out of habit.
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Thanks for that information. I have just requested the part numbers from SNG Barrett. I hope to have an answer to share with this forum soon!
And here is the Denso coils I found, just in case: https://www.ebay.com/itm/32596557294...Bk9SR4SFrdiQZQ

Do they look correct?
Thanks again for educating this noob!

 

Folks,
I just got a quote from a local dealership:

Thank you for providing the price and availability details. I confirm the part numbers (I assume Jaguar P/Ns) as follows:

• Coil (C2S42673): $128.65 each
• Spark plugs (C2S46895): $12.11 each

 

You can look up factory part numbers yourself and save some time:

https://parts.jaguarlandroverclassic...-s-type-parts/

 

if you go with non jaguar branded parts check rockauto. They have oem stuff. Just not jag branded for less

 

The price for the coils seems pretty high. You can get Denso coils and plugs which the car came with for much less at other sources, if you can find them. I replaced mine with NGK coils and iridium spark plugs on my car and they work fine. You have standard spark plugs on you post. The car should have iridium spark plugs, which it came with. They are more expensive than standard plugs, but last much much longer and probably give you better performance and gas mileage too.