Parts Needed to Change the Coil Packs and Spark Plugs in an Aston Martin DB9

Parts Needed for Changing the Coil Packs and Spark Plugs on an Aston Martin DB9
The bits you’ll need

If you have a lumpy idle with your DB9 (like mine was as detailed in this blog post) or are just doing a scheduled service that requires changing the plugs, it will be helpful to know all the parts you’ll need.   Of course, you’re sitting there going ‘Duh – I need spark plugs to change spark plugs you idiot’.   Yes, that’s true, but you also need a small assortment of other bits and bobs to put it all back together Properly.

The list isn’t that long, but I wanted to share the part numbers, sources, prices and other details with you to make your effort easier.    I’ve included a lot of photos too, and at the very bottom of this post (below the video) I have included a photo gallery of each part from various angles in case you are trying to compare something to the official dealer part (like sourcing from a Ford dealer).

Ford LogoSeveral of the parts I discovered are actually Ford items.  Blasphemy you say!?  We’ll, I’m over the surprise of this now, the DB9 includes many Ford, Mazda and Volvo bits.  Sourcing the bits from suppliers other than an Aston Dealer might be possible, and I will note this if I can find them.

PCV Valves Too…

Aston Martin DB9 PCV Valve
The PCV Valve is actual made by Ford

As I embarked on my Coil Pack service, I decided I would also service my Positive Crankcase Ventilation (PCV) valves since they are buried in the same area.   Why?   I have covered this topic separately in another series of articles (starting with this one – please check it out) but the short version is that I spotted the all too common engine oil build up in my air intake plenums, a sign that the PCV valves have failed and are letting oil through.   The parts for this will are included in this blog post, including a cautionary tale to save yourself some major hassles and expense.

Parts Needed

Parts still nestled in their shipping box after a 3 day journey
Parts still nestled in their shipping box after a short 3 day journey

Below are all the items I purchased.  I got them all from HWM Limited in England and shipped to me in the USA.   I was literally stunned when the parts arrived in California just 3 days after I ordered them.  Wow, faster than my regional dealer and vastly cheaper!  Well done HWM.    Here is a copy of the invoice in case you are interested in the details (I ordered some other parts for future projects on the same invoice so pay no attention to those).  If you live in the UK or EU and  are interested in ordering from them, please reach out to the parts team at HWM England and let him know you learned about the parts from this blog.

Coil Pack(s)

12 Aston Martin DB9 Coil Packs
Aston Martin DB9 Coil Packs P/N 4G4E-12A366-AA

There are two versions of the coil packs, the original ‘2-pin’ model (describing the number of electrical connectors it has), or a later ‘3-pin’ model.  I don’t know when the change over occurred (sometime in MY 2006 I’ve read in the forums), so you’ll need to sus this out a bit with your dealer before you order the parts.  My car was the 2-pin version shown here.

[Updated Oct 2021 – I’ve created an article on how to inspect your engine to determine if you have 2-pin or 3-pin coil packs BEFORE you order your parts for the project.  This way you can be certain.  The process only takes about 5-10 mins and would be well worth it.  Check out that article here.]

If you are replacing all of them (which I advocate for in my other post describing the lumpy idle and its cause) you’ll need a quantity of 12 of them, one for each cylinder.

2-pin coil pack for Aston Martin DB9 Part Number 4G4E-12A366-AA
2-pin Coil Pack

Qty 12 – Aston Martin P/N 4G4E-12A366-AA (Ignition Coil and Boot Assembly – 2 pin for early cars)

You can find them online for $105 USD each here, and you can probably get them a fair bit cheaper if you live in the UK or EU by contacting the parts team at HWM England and they can probably give you a bit better pricing if you mention you were referred from this website.

WARNING – Be wary of aftermarket cheap coil packs from China that now seem to be available.  eBay and Amazon now have listings for DB9 coil packs for vastly less money, but I have NO IDEA if they quality and specs of these parts are the same.  Just because they look similar on the outside doesn’t mean they are the same inside.  I may buy one and take them apart to compare someday, but for now I’d recommend you bite the bullet and stay with the genuine (and sadly more expensive) Aston parts.

Spark Plug(s)

Aston Martin DB9 Spark Plug Part Number 07-85126-PK NGK PTR6E-13
Spark Plug Part Number 07-85126-PK

Technically there is no need to change the spark plugs if you are dealing with a failing coil pack, but its good insurance to do so.  Maybe you are just doing your plug change as part of  your 70,000 mile service (ya, right, a DB9 with 70K on it, ha-ha-ha)!

NGK-LogoWhen you open your dealer supplied official Aston Martin spark plugs, out will come an NGK brand model PTR6E-13 spark plug.  I’ve searched some to try and find this exact plug directly from an NGK online source, but no luck so far.  I suspect it’s a bespoke model strictly for Aston Martin (let me know if you find a source for the exact model).

Aston Martin DB9 Spark Plug Part Number 07-85126-PKThey are sold individually (P/N 07-85126), or in slightly cheaper 4 packs (which are more common).

Qty 3 – Aston Martin P/N 07-85126-PK (Spark Plug Vanquish/DB9 Box of 4)

You can find the box of four online for $140 USD,  and you can probably get them a fair bit cheaper if you live in the UK or EU by contacting the parts team at HWM England and they can probably give you a bit better pricing if you mention you were referred from this website.

[Updated June 2020]  I think you should consider a different plug if you run an early model DB9 like me.  Here’s why.  I’ve been working with Velocity AP on applying a new ECU tune to the car to get a few more horsepower (a simple software ugprade you can apply).  The original DB9’s made about 450bhp, then there was a 470 bhp version, and then the DBS makes about 500bhp.  My goal is to get up towards the same power as a DBS.

Later Model Plug

Chris Edgett at Velocity AP (a.k.a. Irish07 on the forums) recommended that I consider fitting later model DB9 spark plugs (MY 08-12) as they run ‘cooler’ and this will allow the ECU to run more advance on the ignition (and make more power).   This isn’t some aftermarket snake oil, its essentially just fitting the same spark plug Aston evolved to on their own.  Now we can take advantage of it in the earlier cars too.

Tech Background – “When a spark plug is referred to as a ‘cold plug’, it is one that transfers heat rapidly from the firing tip into the engine head, keeping the firing tip cooler.”  This in turn keeps the engine from pre-detonating (pinging or misfiring) when it’s under load.  The original plug that came with my DB9 was NGK p/n PTR6E-13.  The ‘6’ in that p/n indicates the heat range of the plug,   The later model year cars have NGK plugs with a ‘7’ heat range, one step ‘cooler’.  Learn more about Spark Plug heat ranges here on NGK’s website.

The plug is Aston Martin p/n 5R13-12405-BA.    Best purchased in a box set of 4 and you’ll need qty 3 of these to get 12 plugs.  The box set of four is Aston Martin P/N 5R13-12405-BA-PK.  You can find these online for about $123 USD each.  These are the plugs I will be giving a try soon.

OEM plug next to NGK ITR6F13

[An Alternative Plug] – Contributor to this Blog Mike (Aston 2209) did a bunch of great research to work out if NGK could just sell us an equivalent plug without the bespoke Aston Martin markup.  He contacted NGK UK and they pointed him at their Laser Iridium Plug NGK p/n ITR6F-13 (4477).   This is the same ‘heat range’ as the original plug (NGK range 6).   They have a tapered fit shoulder for sealing into the cylinder head (same as the OEM).    The good news is that these are notably less money and can be had for under $11 USD each (compared to nearly $25 of the OEM).   You can buy them as a 4 pack for about $42 USD  on   Twelve of these will cost you under $130 USD, a considerable savings over OEM.    Note:   I’m not sure this is a corner I want to cut since the plugs are very difficult to reach.  Keep in mind that I have not run this plug first hand, but Mike has with good success.

Intake Manifold Gasket(s)

Aston Martin DB9 Intake Manifold Gaskets Part Number 1R12-08-10077-PK
Intake Manifold Gasket Set P/N 1R12-08-10077-PK

You may need 1 or 2 of these, depending if you are removing just one intake or both.   If you remove an intake manifold, REPLACE the gasket every time.  Don’t reuse and risk a leak.   It will ‘position’ slightly differently each time its installed (even with the aligners), so it may not work right the second time around.

They are available individually (P/N 1R12-08-10077) or significantly cheaper in a more common 2 pack set (which is what I bought).

Quantity 1 – Aston Martin P/N 1R12-08-10077-PK (Gasket – Inlet Manifold/Head 2 Pack)

The gaskets aren’t cheap.  You can find it online for $353 USD, and you can probably get them a fair bit cheaper if you live in the UK or EU by contacting the parts team at HWM England and they can probably give you a bit better pricing if you mention you were referred from this website.

Fuel Injector O-Ring – Upper and Lower

Aston Martin DB9 Fuel Injector with O-Rings
Upper (Blue) and Lower (Green) O-Rings

Part of removing the Intake Manifolds requires removing the high pressure fuel rails and fuel injectors.  Each fuel injector has two o-rings, and upper and a lower.  The O-rings create a pressure seal for the fuel, and its cheap insurance to replace the ones that have been baking in the bowels of the engine for 10 years with a new set of supple ones.

The upper o-rings that engage the fuel rail are Blue.  The lower O-rings that engage the intake manifold are Green.  Different sizes, not interchangeable.  These are Ford parts, and made in the USA.  See my extra photo gallery at the bottom of the post if you want to see all the info on the boxes to try and search them out at a Ford dealer.

Blue (Upper)

Aston Martin DB9 Fuel Injector O-Ring Upper Part Number 6G43-08-10474-PK
Blue Upper O-Ring P/N 6G43-08-10474

They are sold individually or in packs of 8 (since the part is shared with the Vantage or other Ford and Jaguar V8’s I guess).

Quantity 12 – Aston Martin P/N 6G43-08-10474 (Seal – Fuel Injector to Manifold – Blue)

You can find the 8 pack online for about $40 USD (you’ll need 2 packs to get enough), and you can probably get them a fair bit cheaper if you live in the UK or EU by contacting the parts team at HWM England and they can probably give you a bit better pricing if you mention you were referred from this website.

Green (Lower)

Aston Martin DB9 Fuel Injector O-Ring Lower Part Number 6G43-08-11260-PK
Green Lower O-Ring P/N 6G43-08-11260

Quantity 12 – Aston Martin P/N 6G43-08-11260 (Fuel Injector O-Ring – Green)

You can find the 8 pack online for about $42 USD (you’ll need 2 packs to get enough), and you can probably get them a fair bit cheaper if you live in the UK or EU by contacting the parts team at HWM England and they can probably give you a bit better pricing if you mention you were referred from this website.


Here is a short video where you can see more detail about the parts.

Below are photo galleries of each part from all sort of angles (in high resolution), maybe one of the views will answer some question you have.

Coil Pack Photo Gallery

Spark Plug Photo Gallery

Intake Manifold Gasket Gallery

O-Ring Photo Gallery

41 thoughts on “Parts Needed to Change the Coil Packs and Spark Plugs in an Aston Martin DB9

  1. Pingback: Lumpy Idle / Misfire on an Aston Martin DB9 – Aston 1936

  2. Mark Chippendale

    70k on a DB9!! Haha haha haha…
    My 2005 model has 74k on the clock – admittedly it did have a new engine at 33k, which is good because I won’t need to change the plugs and coils for another 29k! Shame about the crappy paintwork…
    Great articles, keep up the good work!


  3. Les Leese

    Hi Steve I want to congratulate you on your blog and the quality of your write ups. I am hoping to take delivery of my DB9 in about 2 wks time. It’s a 2007 MY. I find your blog to be very informative and although I have some experience with the spanners (mainly on Porsche ) I will have considerably more confidence when I carry out any work on the DB9. We’ll done and keep up with what is an excellent blog.

    Les (UK)

    Sent from my Samsung device


  4. Ben

    Great blog, Steve! May have to do the same on an ’07 DB9, though right now a couple of bottles of fuel injector cleaner (Techron) seem to have cleared the misfire (Cyl # 8) that showed up once on the ODBII reader (no more codes triggered after some trips to Sacramento)

    Looking forward to your chronicle on the coil/spark/PCV replacement.

    Ben (Reno,NV)


    1. Coming up in the next few weeks. Working my way through the footage and preparing the blogs takes a while, sorry I don’t have it all posted yet. Probably a post a week, maybe two if my work schedule allows. Stay tuned.


  5. Paul Rogers.

    Hi Steve, i’ve been looking at the photos of your new ignition coils, there seems to be 4 small blobs of silicon grease in the rubber boot to the end of the spring is this right?, do I need to put a small amount of silcon grease inside the rubber boot.
    I’m doing this job in a few more weeks so looking forward to reading some more posts, plus anything to keep an eye on whilst doing this job? You can email me if you like.


    1. Those blobs were just there in the boots when I took them out of the box. Not added by me. I presume they were silicon, they weren’t grease. The old ones removed did not have the blobs. I think they are for helping keep the wire coil centered while you are blind trying to hit the top of the plug connection, where without it the wire coil could push aside. Good spot.


  6. Fred

    Best blog for Aston Martin DB9 owner!! It really helps me a lot!

    Btw Steve, have you still order parts from HWM? I ordered parts from them, paid already, no reply at all until now (almost a week) and I personally emailed Rob Sims also no reply.



    1. Hi Fred. Thanks for the kudos. Yes, HWM is still my source, but I haven’t ordered anything for a few months (which shouldn’t matter one hopes). Rob was fairly responsive for me, perhaps he’s on some PTO. Regardless, they should be looking after you well. Did you order using the web, or talking to a sales rep? Hoping things show up for you quickly…..


  7. Pingback: Preparing and Installing the Coil Packs into an Aston Martin DB9 – Aston 1936

  8. Paul Drula

    Hi Steve, I have a 2005 DB9 with 30K miles and have been experiencing all of the same problems you have written about in your blog, lumpy idle which has been getting progressively worse, oil residue in the throttle bodies and filter, and a sagging headliner! I have been searching the internet for information about the various issues and came across your blog. I can’t even begin to tell you how excited I was to find that someone (you) has taken the time and effort to produce such informative and extremely helpful information. I have ordered the parts and I’m anxious to get started on the repairs. I’m curious to know if you are you going to post the information on the PCV and headliner repairs soon.


    1. Hi Paul. Glad to hear the blog is helping. If you bought the PCV parts, its not too hard. If you got the PCV assemblies (where they are mounted in the pipework already) its not too difficult to swap them in. If you just have the PCV valves, its a bit more work. At the pace I am going, it may take through Xmas to get the whole series posted, but reach out again if you are going ahead before then and I can share some of the raw video with you to see the process.


      1. Paul Drula

        Hi Steve,
        I just started to work on changing the coil packs and hope you will be able to share the raw video on changing the PCV valves. I have run into an initial problem though, right from the start the side cross brace torx screws won’t break free (the main cross brace did) and I’ve tried all of the techniques to remove them without any luck. Do you think the manifolds can be removed with these side cross braces in place? Thanks, looking forward to your response.


    2. Hi Paul,

      I was rummaging through PistonHeads and thought I might have spotted your comments paulrog1 or something. If this was you and you used, I’d like to pick your brain about swapping the boots and springs on the coil packs. I couldn’t figure out how you could remove the spring from the old coil pack. Please let me know and I can let you know what I am interested in learning about. I am really looking for all the ‘alternate source parts’.


  9. Pingback: Installing the Intake Manifolds into an Aston Martin DB9 – Aston 1936

  10. Pingback: Installing the Fuel Injectors and Fuel Rails in an Aston Martin DB9 – Aston 1936

  11. Paul Drula

    Hi Steve,
    Just a quick follow up note, the intake manifolds did remove fairly easy without the side braces being removed. Also, I’m ready to tackle the PCV valves, do you have the video or blog ready for this chore?


  12. 70k..!!! Mine has just over 85K and the service book is up to 130K of servicing.

    I found this site looking for issue I have with misfires and unsettled idle, I suspect that I need to undertake this project and with all the details of the parts, it has saved me a mountain of time – did you change the fuel rails at the same time as I have read elsewhere these do need changing around 50-60K miles??


    1. Hi Demon. I didn’t have to deal with the fuel rails. Not sure why they would need changed unless they are corroding (they are just pipes with formed cups on the ends). Replacing them would be somewhat difficult as disconnecting them from the fuel lines is in an incredibly space constrained location. Possible, but won’t be fun. I have some shots of the location in one of my videos on the coil pack swap. Removing the rails will need a small assortment of replacement plastic tie-wrap fittings since you’ll need to cut off the existing ones that hold the injector wiring. Hope you enjoy the site!


  13. Thanks Steve, I assume mine are ok, just having read some have had to replace them, thought it might be a job to do whilst undertaking the coil/sparkplug project.


  14. Jonathan

    Hello Steve,

    I am glad I found this informative page online. Thank you for taking the time and effort to create this wonderful wealth of resources for us fellow AM owners.

    My 2005 DB9 just began to misfire and unfortunately, the nearest dealership is almost 50 miles away. I brought my car to a nearby independent shop but without an AM propriety computer, the OBD reader only returned a P300 random misfire code.

    What’s interesting is that my car’s coil packs and spark plugs (all 12 of them) were just replaced by an AM dealership in June 2015. It’s really hard for me to imagine that one (or some) of the coils is already failing.

    Have you ever heard of replacement coils failing in such a short amount of time? Could there be anything else that might’ve caused the misfiring issue?

    Your help is greatly appreciated.

    Many thanks!


    1. Glad you are enjoying the site, its exactly why I made it. Curious problem. Was it smooth after the 2015 service, and the problem has come back, or was the problem there after the service? There is the potential its the fuel injectors, but I would think that wouldn’t be random and could be traced to a specific cylinder. They are certainly easier to get to. Combustion is just fuel, spark and air. I’d used the OBDII and check the fuel rail pressures, then do some head scratching.


      1. Jonathan

        The car ran smoothly without problems after all the coils and spark plugs were replaced in 2015. However, in less than two years/3k miles the misfiring issue returned to haunt me.

        I’ll have the shop check the fuel rail pressures. I really hope it’s something other than the coils or spark plugs that’s causing the problem this time.

        Thank you for providing the pricing information for all the parts needed as well. What’s the best way to order from HWM? Did they provide you with the AM one-year warranty with their parts?


      2. I’ve contacted Rob Sims at HWM by email each time I need bits. The email should be linked to his name in the parts article. Tell him Hi from me when you reach him.


  15. Jonathan

    Thank you again for your help, Steve.

    I’ll reach out to Rob and report back as soon as I have information to share about what happened to my car.


  16. Jonathan

    Hello Steve,

    I wanted to thank you for providing all the useful information on your website. I was able to order all the parts from HWM (through Michael whom was referred to me by Rob) for this job. And fortunately, the culprit was the coils and spark plugs. The independent shop was unable to identify the particular coil or spark plug that caused this issue but after replacing all 12 of them, the car runs like it should be again.




  17. John Wagner

    Just an FYI, I am about to change my plugs and coils. I found the coils and intake gaskets here: for a bit less than at Scuderia. they do *not* have the injector O-rings though. I bought those at Scuderia – before I saw Steve’s video on having the injectors cleaned/rebuilt. I wish I had seen that first 😦


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