Expert: Rob Painter - 4/6/2011

Question
QUESTION: Hello,

 I am having trouble locating my spark plugs on my 2004 Deville (base). I have changed spark plugs multiple times but this is the first time I have done a transverse engine. As you know they are different than a longitudinal so where are the spark plugs? I fear the worse i.e. I may have to take my car to a shop which kills me because up until now I have done all the work on my vehicles! Along with your answer please send me a map/ illustration for the location of the spark plugs.

ANSWER: Hello,

I have no illustration, however all you need to do is follow the wires. Do one at a time and when you get to the rear, be prepared to tear your hands up literally!

Here are some tricks on a transverse engine that are not in the book--I have not replaced the plugs on this engine, but I have on many transverse engines and I will tell you the rear is not fun!

You need a 5/8 spark plug socket with a swivel, preferably 3/8 drive with various extensions.
You will need to be prepared to remove the wires and chances are they are stuck on the plugs. A straight pull will destroy the wire. Spark plug wire removal tools don't work well either. Now, you need to be very careful with my suggestion, but it has worked well for me. At a parts store, you need two things. Bring in the pliers and buy about 6" vacuum line that will slide tightly over each jaw. Buy another 6" piece of vacuum line that will fit on the tip of the plug. Buy a tube of clear silicone (not adhesive).

Now, when you go to remove all wires, use your specially equipped pliers and put around the spark plug boot horizontally paralleled with the manifold. This way you don't damage the boots. You need to grip the boot and twist back and forth until the wire is loose from the spark plug and remove. Gap your plugs and change the front 4 first. One plug is removed, install your vacuum line on the tip of the new plug. You will find no matter what the angle, the hose will line up the plug and you can screw in and tighten with the socket. Put silicone around the plug. This will make your wires come off easily next time. Install the wire. Go to next plug and so on.

Because of the angles, you will find it difficult to change the rear plugs, but play around with extensions so you get a good angle and maybe you might not need and extension. You do need an angle somewhat straight where the swivel is not binding, or you will break the plug, which normally is not a problem, but sometimes challenging to get the broken end out of a spark plug socket.

See, even if you had a diagram, there is no book I am aware of that will give you the real life application and I think you will find my suggestions pretty handy.

As I said though, the rear has very limited access close to the firewall.

One other tip you may consider because I have been involved investigating so many Cadillac fires over the years, here is something that few are aware of. The main plastic fuel feed which is about 6" in length with quick connects can fracture because of age and spray gasoline as far back as the rear exhaust manifold there by starting an engine fire. After your tune up, if you smell gas, shut the engine off immediately and change this Cadillac fuel line!

After your tune up if you don't smell gas you are good. It's just something I have dealt with since they came out with since their fuel injection and 60 psi was introduced. These lines become brittle over time and inadvertently touching it on the driver's side front of the engine below the air filtration. can create a hair line crack. You will probably be fine. I just want to make you aware. By the way, that is not in a book either!

Hope all this helps you and let me know if it does. Even if you had a diagram, unless you are changing the wires, it is not going to help you anyway, because the wires split off into looms. All you need to do is feel your way to the boots.

Good Luck!!!!


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---------- FOLLOW-UP ----------

QUESTION: Greatly appreciated answer..I have followed the wires to a VERY hairy situation...the plugs are under a "coil pack" I have noticed that has a plastic covering on it with an added demon of some sort. There is a piping-mechanical doohicky attached/ bent across the middle of my coil packs in the rear (see attached image)engine. What the ungodly is that and how do I get it off? I removed all (3) of the bolts I could find on this apparatus but it wouldn't budge enough to remove anything. What do I do now? I am balding so I don't have any spare hair to pull out!!!

Answer
Hello,


For some reason, I cannot see the image you attached. I had also stated, I had changed plugs on many transverse engines, but not in that type of car.

OK, you want to save money, work on your car and keep the remaining hair you still have. I can relate to that.

I am going to recommend something that I feel you now need if you want to do your own maintenance and repair and this is what I do when I get into trouble on a specific car. This is a tool you must have to do any work on the car.

I advised you on the tips and secrets as to how to change the plugs, but to be honest, I flat out forgot about the goofy stuff these manufacturers do when designing their engines. What you are running across is the type of garbage I had to do to change valve cover gaskets and other things.

The tool you need evidently is the factory service manual and once you see what is included, you will find it should take all your frustration away at least as far as what needs to be removed and reinstalled. I guess there is no simple tune up any more.

It costs $30 to become a member. Once you are a member you can download the manual for your car for a year and you can have this information instantly. The site for the factory manual is http://www.alldata.com.

I did my best to give you all the information needed to change the plugs on a transverse engine, but it has not been common for me to run into situations like you have on your Cadillac, but it doesn't surprise me either.

I hope this helps you.

Let me know if the manual made your life simpler on this adventure.

http://www.autotheftexpert.com