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Thread: 2003 KIA Sedona - Changing Spark Plugs

  1. #1

    Post 2003 KIA Sedona - Changing Spark Plugs

    NOTE: This article will be updated shortly. If you wish to access the latest version of these instructions (March 2014), I have created a downloadable .PDF document for your access at the bottom of this post.

    This is not the typical place to post tips on working on a KIA, but it may help a few people. This step-by-step guide should work closely to all years of the Sedona with this engine combination.

    A friend of mine has one of these ... uhh ... Mini Vans, and the typical "Tune-Up" charge is over $700.00 because you must remove the upper intake manifold plenum to gain access to the rear three spark plugs. This article will show you how to gain access and change your own spark plugs WITHOUT paying $700.00! I volunteered to help her with some problems on her van last weekend.

    The KIA Sedona has a transverse-mounted 3.5L V6 engine. The front three spark plugs are easily accessed by simply removing the plastic engine cover. The ignition design is a 50% Coil Over Plug design. I say 50% because there are only three coils over the front three plugs. The rear spark plugs each have a plug wire to them from one of the three coils up front.

    First, you need to prepare yourself for the task at hand. BE PATIENT !! I cannot stress this enough. This car is not 'difficult' to work on, but it is still an evil bastard at certain times.
    You will need a small assortment of metric hand tools (3/8" and 1/4" Ratchets, sockets (primarily 10MM, 12MM), Combo Wrenches of the same), it helps to have gloves too. You may like something such as the Mechanix Wear brand we carry here in our website, or a latex gloves. These will help protect your hands.

    Please use something to sort the fasteners as you remove them. You do not need to label each one them, just group them (intake cover, intake plenum, etc). If you feel you need to just write on a piece of paper and place the fasteners over that location on the paper, fine. You could also use plastic cups or something similar if you wish.
    STEP 1:

    Remove the NEGATIVE cable (black) from the battery.

    STEP 2:

    Remove the air intake tube. This is mounted on the front of the vehicle just in front of the engine and connects to the air box (where the air filter is). There is just two bolts that hold it in place (one on either side), and the hose/line clamp at the air box. All you need to do is loosen the hose clamp and the assemble will slip off. (see image below ... NOTE: this image is from a newer Sedona so the air intake tube may be slightly different on your vehicle).

    The air intake is YELLOW and the arrows point to the two bolts.

    STEP 3:

    Remove the engine cover. There are (6) bolts that hold it in place.

    Remove the bolts (DO NOT LOSE the rubber shock washers that may be attached to the bolt or stuck to the plastic cover) and then take off the oil filler cap and lift the cover out of the way. Be careful not to drop a bunch of crap into the open oil filler hole. Replace the oil filler cap.

    The image below shows the cover bolt locations.

    With the cover off you can now see the intake plenum, valve covers, coil packs, plug wires, and more.

    STEP 4:

    Remove and Replace FRONT three spark plugs. Yes, we might as well get this easy part out of the way first.

    Each coil pack is held in place with two bolts. You will not need to disconnect the wire harnesses from the coil. First remove the plug wire boot from the coil pack. When you remove the bolts you can lift the coil pack up. NOTE: The spark plug boot for that cylinder is attached to the bottom of it ... lift SLOWLY and then use your other hand to pull/bend the boot up and out of the hole.

    You can now take a long extension and 5/8" spark plug socket to remove the spark plug. It may be a problem getting the plug up if you are not using a spark plug socket. I highly suggest using a piece of rubber hose that would slide over the top of the plug to remove it, as well as to get the new spark plug started in the hole to prevent cross-threading and damaging the cylinder heads. I use this tool (image below) which is a flexible plug starter that has an inner drive so you can twist the top to get the plug started. Most tool suppliers have something similar.

    IMPORTANT - You better make sure you are installing new platinum tip spark plugs. You want this tune-up to last another 100,000 miles and no one wants to do this spark plug change on a regular basis. DO NOT use gimmick plugs! Just an OEM replacement is perfect.

    1. Verify the spark plug gap on your new spark plugs before installation. The sticker under the hood tells you what the gap is supposed to be (typically 1.1mm). Using a gaping tool to check/set the plug gap.
    2. Make sure you install a small amount of anti-seize lubricant on the threads of each spark plug to prevent future problems.
    3. When you tighten the spark plugs in place, make sure you DO NOT OVER-TIGHTEN and strip the threads. I like a pink-knuckle tight, just enough to seal the plug taper into the cylinder head.

    Once all three front spark plugs have been replaced you can reinstall the coil packs. Slide the boots down into the hole onto the spark plugs. They should go on freely. Tighten the coil packs into place and reinstall the plug wires.

    STEP 5 - The FUN Stuff

    Time for upper intake plenum removal.

    1) Of course I forgot to take a picture of the harness heat shield/support bracket that attaches to the intake plenum. Probably because this component pissed me off. Behind the oil filler cap you will see a large diameter wire harness inside convoluted tubing. It is plastic wire tied to a metal bracket that has two bolts holding it to the intake plenum.

    Remove the two bolts and pull the bracket forward so you have access to the intake plenum bolts. It is VERY possible that the three plastic ties are going to crumble in your hands and fall off ... so be it, they're junk. If they break off just set the bracket aside. You'll be able to use it as just a heat shield later. Thread the two bolts back into the holes so you do not lose them.

    2) Unbolt the air box (air filter box). There are four bolts easily accessible on top perimeter. Once you have it unbolted you need to disconnect the inlet line from the air intake. First remove the vacuum line toward the front. The connection of the air inlet is another hose clamp to loosen (do not take the screw all the way out of the clamp. This hose may be difficult to remove. Wiggle, twist, etc ... it WILL slide off.

    3) Right below where the inlet hose connected to the throttle body is a vacuum line. Disconnected it. Use pliers to squeeze the clamp as you twist/pull the line off. (there is a Throttle Body image below that shows this line)

    4) On either side of the intake there are brackets that hold various electronic connectors, lines, etc. You need to unbolt these brackets and then thread the screws back into their locations so you know where they are when you start reassembly. These are going to give you the room you need to move the plenum around once you unbolt it.

    5) You are going to have some of the same connections in the back of the plenum that are not only hard to get to, but stubborn.

    On the driver's side back of the plenum you are going to see two large connectors just behind the throttle body. One is black and sort of oval-shaped, and the other is yellow and close to square. To remove (unplug) these connectors there is a button to depress on the connector that will release it.

    Look at the images below for location and identification for some of the above descriptions.

    TIP: You can remove the brake booster vacuum line (not labeled) at the top right of the image below for additional wrench clearance from the back of the intake manifold. There is no need to remove it from the brake booster itself.

    This image below jumps ahead a bit, but shows you the two connectors I have mentioned above that need to be disconnected.

    6) From the image above (this is showing the upper back of the engine with firewall and heater hoses to the left) you can see two brackets coming up from the cylinder head/engine block. These are supporting brackets for the intake plenum with bolts that are a bit of a test to get to.

    There are four bolts that come from the rear into the plenum ... two on each bracket. The bracket on the left is actually two parts and you are not seeing the upper portion with the engine lift eyelet that sits over the top of the plenum.

    Remove these four bolts, then remove the last (fifth) bolt from the upper engine lift bracket.

    7) You will now unbolt the upper plenum from the engine. There are two nuts (on studs with lock washers) and five bolts.
    NOTE: These bolts are clamping/sealing the plenum gasket. BE CAREFUL when you start to lift up the plenum. If you are VERY careful you might be able to reuse the gasket. It is best if you replace the gasket, but some people are trying to save every penny.

    8) Now you have hopefully unbolted everything and can now lift up the plenum.

    Perform a simple visual inspection to make sure everything is out of the way. When you lift the plenum up, if something falls into the open ports you could damage or destroy the engine. You want to make sure NOTHING can fall into the engine. Have some clean rags ready so that you can place them in or over the holes as precaution.
    CAREFULLY lift the plenum straight up to clear the mounting studs.

    I purposely did not instruct you to disconnect more items on the driver's side of the engine under the throttle body area. You do NOT need to take anything else loose! Once the plenum is up you will twist it forward on the passenger side (front of the engine) to allow access to the rear spark plus as shown in the images below.

    STEP 6:

    You will now CAREFULLY twist and lift the plug boots up off the spark plugs.

    I cannot stress how crappy the OEM plug wires are. They are easily damaged. If you damage them in ANY way at all you will need to replace the plug wire set. There are only (3) wires in the set and will cost you anywhere between $60-120.00 depending on the brand and where you get them.

    With the boots removed you will now follow the procedure above for setting plug gaps, applying anti-seize, and installing the new platinum spark plugs. Reinstall the plug boots.


    Now it is time to put everything back together in the opposite sequence as described above. I've listed just a few tips below:

    • Replace the intake gasket if necessary.
    • Make sure the harness plugs in the back of the engine are not in the way (wrong side of the bracket) when you set the plenum in place.
    • When you reinstall the plenum, set it down carefully and squarely.
    • DO NOT tighten the bolts when you set the plenum in place.Just start ALL of the bolts, including the supporting bolts on the rear brackets of the plenum. If you do not follow this step you may have bolt alignment issues later. Just get each bolt started, and THEN you can tighten the plenum down to the engine.
    • TIGHTEN THE PLENUM IN THE PROPER SEQUENCE. This means that you tighten each bolt a "little" in sequence, going a bit tighter each time through until the plenum is fully tightened. 3-5x around is typical. (see image below)
    • Once the plenum is tightened you can then tighten the rear bracket bolts.

    The rest of the re-install procedure is should be straight forward and now your KIA Sedona will be running good for a long time.

    In Closing:

    This particular vehicle was part of a factory recall regarding cylinder head gaskets or something, so the dealer (now out business of course) had worked on this engine while under warranty.

    She had told me that "some shop" had performed a HALF tune-up on it some time ago. Yeah, a HALF of a tune-up! The shop only replaced the front three spark plugs and ignored the rear three. Way to go idiots!

    I asked my friend the typical symptoms she was seeing before I started working on it. "Misfire during freeway acceleration" was her #1 statement. When I got to the back three rear spark plugs I could not believe what I found.

    The plug boot on the #1 cylinder was destroyed by what seems to be someone previously using an object to pry up a sticking plug boot, and DESTROYING it, most likely causing a misfire. This plug boot should have been replaced, and the ONLY people to have worked back there on this vehicle was the dealer during that warranty repair.

    Not only was the boot itself destroyed, but the shielding on the plug wire just within the top of the boot was cut, allowing easy access for spark energy to escape and not make it to the spark plug.

    Of course I replaced all of the plug wires on her Sedona.

    Attached Files Attached Files
    Best Regards,

    Samuel A Solace - Pres/CEO
    Century Performance Center, Inc.
    ph (775) 746-4887
    fax (775) 624-8865

  2. Thumbs up kia sedona tune up

    your instructions are excellent and to the point;thank you

  3. Default A quick question or two

    Quote Originally Posted by orlando420 View Post
    your instructions are excellent and to the point;thank you

    Will the coil packs on a 2004 kia sedona cause it to not want to start and cause it to die while driving? I was driving and the engine shut down all of a sudden. Any response will be greatly appreciated. Thank you in advance.

  4. #4


    Hello Zigvab,

    My apologies for the accidental ban. I do not believe a simple coil swap will cause intermittent stalling or a no-start condition. The coil is the same for the 2002-2005 model years. You can have issues if the coil is cracked/defective. If it runs good when it runs, here are a few tips.

    A no-start is often times the crank sensor, or can be associated with no fuel. I would first use a scan tool and see if there are any codes present, whether the check engine light is always on or not. The stalling could be crank sensor or fuel related as well. Make sure all ground wires are clean and properly secure. Remove them, move them around a bit and re-tighten.

    Other items of interest:

    Some people have stated a variety of causes to the problems you describe. From the throttle position sensor, the starter itself, and even a defective voltage block or other wiring issue. If you have a considerable amount of miles on this vehicle, make sure the catalytic converter is not clogged or failing (they start to wear out after about 50,000 miles, but will survive twice that if the overall engine condition is optimum).

    Many Kia customers and mechanics have complained about problems that have not triggered codes (or a code that was not the real problem). Dealer mechanics are often as perplexed as everyone else when this occurs.

    Can you provide more details about the vehicle ... mileage, any recent repairs, etc?
    Best Regards,

    Samuel A Solace - Pres/CEO
    Century Performance Center, Inc.
    ph (775) 746-4887
    fax (775) 624-8865

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