Tuesday, October 16, 2007

SAAB 9-5 spark plug replacement

The 2.3 SAAB 9-5 has the smoothest access to the spark plugs of any car I’ve ever owned. I have to go all the way back to my first car, a V8 Ford Granada, for second place.

Every car I’ve owned between the Granada and the 9-5 had at least one spark plug in such an awkward spot that seemed the engineers must have drawn a spark plug in space and then built the car around it.

The 9-5, on the other hand, has all four plugs right on top. No need to find a socket wrench capable of bending like a Calabi-Yau manifold to remove any of the plugs.

I’m not experienced with the V6 SAAB 9-5 and can’t speak to its spark plugs.

Tools you need:
Socket wrench and extender
5/8 spark plug socket
27T torx screwdriver
Spark plug gap tool
Dielectric grease (not pictured)
Small flathead screwdriver (not pictured)

Before lifting the hood, take time to gap the new sparkplugs. The plugs I purchased came pre-gapped to the correct size, but always check for yourself with the gap tool.

The stock plugs for my 9-5 are NGK BCPR6ES-11 ( the hotter NGK BCPR7ES-11 also fit), the gap is 0.039 inches or 1mm. The aero 9-5 can also use these or it can use the hotter plug.

The removal and installation of the spark plugs starts as most automotive work does, by setting the parking brake and disconnecting the battery. First you remove the direct ignition cassette. It sits in the center of the valve cover and is held in place by four 27T torx screws.

Lift the cassette straight up to remove it, a little rocking motion might help get it started as you pull up. Disconnect the wiring harness by sticking the flathead screwdriver between the red side and the main part of the connector. Pry the red side away and the harness should pull the rest of the way out with no difficulty. Set the direct ignition cassette out of the way.

I read online that the cassette should generally be kept upright, that way you don’t have to wait for the oil inside to ooze back into its normal nooks once the cassette is reinstalled. They said it saves time and helps protect the cassette.

The spark plugs are now exposed. Use the socket wrench with extender and 5/8 socket to remove the plugs. Check the condition of the old plugs; there is a whole science to spark plug wear. Websites with typical wear pattern descriptions can help you.

The new plugs can now be installed. Smear some dielectric grease on the insulator of each plug before setting in the 5/8 socket, then use the socket and extender to carefully get the plug threaded. Once the plug is most of the way in, the socket wrench can be added to secure it. Use a torque wrench set at 21 ft-lb or just use your socket wrench to turn the plugs a quarter turn past snug. This will seat the spark plugs without over tightening. Too tight and you can break the plugs, or worse, damage your engine.

The direct ignition cassette can now be reinstalled by setting it straight down, connecting and locking the wiring harness, and then pressing the cassette the rest of the way down. A small amount of wiggling might be needed to line up the holes for the four torx screws. Tighten the four screws in an X pattern, give each screw two passes to make sure all of them are hand tight. That is all there is to the process, you are now ready to start the car and admire your work.

Don’t forget to clean up and put away all of your tools.

Indexing: I’ve never done this myself (on any car), but some people take time to index the spark plugs by adding special washers to make sure the tip of the plug points in the optimal direction. This technique might be of interest to folks with a highly staged SAAB. NGK says that indexing is only necessary for “racers” and any gain will be around 1% (so about +2bhp on a stock 9-5). I have nothing but the most basic idea of how the process works, obviously there are better sources than me on the topic of indexing.

I have a confession to make to my readers that have made it this far. Despite the strong warnings all over the internet, everything from “your car will blow up” to “non-NGK-plug users smell of elderberry”, I have installed Autolite platinum spark plugs in my SAAB 9-5 instead of the stock NGK brand. So far I have 3k miles on these plugs and I haven’t had any problems with them. My ignition cassette is functioning, no misfire OBD-II codes, everything is fine so far.

I will post an update if I ever do run into problems, but I really don’t expect any. I’m willing to eat crow if I’m wrong. I’m also willing to risk my cassette to help prove that a different brand of plug won’t cause any problems. In the mean time, no flaming please.

04-25-08 UPDATE:

No issues with the Autolite plugs for the entire Autolite plug experiment. I would not hesitate to use the Autolite plugs again, but my test is done and I'm back with the NGK plugs. I purchased the NGK spark plugs from TheSAABSite; they were the same price as the Autolite plugs were from the local store. There is no cost savings for me at least, only the convenience of picking up the Autolite plugs from the corner auto parts supplier.


  1. [...] also in the middle of another spark plug experiment. As I confessed at the end of this post from October, I installed Autolite platinum spark plugs in my SAAB 9-5 instead of the stock NGK [...]

  2. Thanks for the info. I just put Autolite platinums in my 2000 Saab 9-5 wagon.

    No problems two days in. If you are on facebook feel free to join my page, Kalamazoo SAAB Network

    Thank you.

    MIke Kilbourne 1999 9-5 SE 2.3 TD04, 2000 9-5 wagon 2.3

  3. That's good news. There's a lot of people that get downright upset when they find a 9-5 owner using non-NGK plugs. Like I posted, I never had problems with the Autolite set I installed.