Spark Plugs & Ignition Wires

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Replacement Parts

Spark Plugs:

NOTE - Because of the relative complexity of changing plugs on the VR6 engines, don't even think about using a non-platinum or cheaper plug.

NGK's Part Number Explanation (PDF)

1995-1997EV Engine
I-5 Engine Code ACU


B =14mm thread
P = Projected Insulator type
6 = Heat Range (between 2-11)
E = Thread Reach 19mm (3/4")
T = 3 ground electrodes

1997-2000 EV Engine
VR6 12V Engine Code AES


B = 14mm thread
K = 5/8" Hex Size; Projected Tip
R = Resistor
5 = Heat Range (between 2-11)
E = Thread Reach 19mm (3/4")
K = 2 ground electrodes
U = Semi-surface discharge
P = Premium Platinum

2001 - 2003  EV Engine
VR6 24V Engine Code AXK


P = Premium Platinum
Z = Extended Gap
F = 14mm thread, 19mm thread reach,
        5/8" Hex
R = Resistor
5 = Heat Range (between 2-11)
D = Special Design Firing End
11 = 1.1mm Gap (.043)

Ignition Wire Sets:

1995 - 1996 L-5 = VW # 074 998 031A

1997-2000 12V VR6 = VW # 021 998 031B or KARLYN-STI # ZVW 311 001

2001-2003 24V VR6 = No plug wires, direct connect

Use OEM quality only!!  And I recommend that you do not buy any third party wire sets.  Purchase your wire sets from either a VW dealer, on any of the specialized EuroVan or VW on-line parts houses such as "The Bus Depot", "EuroParts-SD", or any others that sell similar high quality OEM parts.  Stay away from Pep Boys, AutoZone, Kragen, and others that have lower-priced, lower-quality 3rd party brands which may or may not fit correctly.

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Changing Spark Plugs

(I'd welcome anyone with an I-5 engine to provide photos and procedures.)

NOTE - This task may be too difficult for the average do-it-yourselfer.  Physically changing the plugs is not that difficult but there are several coolant lines, vacuum hoses, and electrical connectors that must be removed in order to gain access to the spark plugs.

The OEM spark plug installed by VW is a premium platinum tip design which should easily last the 40,000 miles when they should be replaced.  There is no periodic maintenance required and if you go to all the effort to remove them just to clean or check them, you might as well replace them.


  • 1 - ratchet socket wrench, preferably 3/8" drive
  • 1- 12" long socket extension
  • 1 - 6" long socket extension
  • 1 - 5/8" spark plug socket with the rubber insert to grip a spark plug
  • 1 - 5/8 spark plug socket without a rubber insert (more about this later)
  • 1 - 10mm socket
  • 1 - small tube of anti-seize thread compound
  • 1 - piece of rubber of vinyl tubing, 3/16" ID about 18" long
  • 1 - each of a straight tip and Phillips tip screwdriver
  • 1 - torque wrench
  • 1 - spark plug boot puller tool (only needed on the AES engine)

    These commercially made tools will sell for $20-$50 and they are available through,, and a number of other sources such as a well stocked local automotive supply house.  Try for "VW spark plug boot puller".



    TIP - If you have a digital camera, take pictures of the engine area every time you remove something.  In that way, you will have a photographic evidence of how to put things back together correctly.  Don't trust your own memory.

    MORE TIPS - Of course, make sure that the engine has completely cooled down.  And because you will be working around the radiator fans and other electrical connectors, I suggest that you remove the negative cable from the battery to avoid ground or shorting out anything.  You should also remove the belly pan for two reasons: one is access the wires on the radiator fans (more about that later) and secondly, to retrieve the inevitable socket or nut that you will drop through the engine compartment.


    Procedure for 12V VR6 (1997-2000):

    1. Remove the large plastic cover.  It is held in place by some plastic clips where it hooks onto the main air inlet tube.  With that cover removed, you will now see that there are a multitude of items that would need to be removed to get to the spark plugs and wires.  I will describe most of them here but you may find it more convenient to leave one or more items in place or more convenient to remove an additional item.  Use the digital camera to record the position of everything. 

    2.  You will need to remove the large black plastic air intake tubes that connects the air filter box to the throttle body.  This large black plastic tube looks sort of like the letter D in that it has a U-shaped tube on one side.  This large diameter air intake tube has a hose clamp at each end.  On the left side, the hose clamp connects it to the air volume meter which is another short section of air tube.  This air volume meter has the large electrical connection at the top.  On the right side of the air intake tube, the second hose clamp connects it to the throttle body.  Completely loosen both of these large hose clamps.

    3. It is advantageous to disconnect the clamps holding down the lid of the engine air filter.  This will allow you a little wiggle room to remove the large air intake tube from between the air volume meter section and the throttle body.  I actually removed not only the lid but the entire air cleaner box along with the cabin pollen filter housing.  The air volume meter section is held in place to the air cleaner lid by three screws but I suggest that you leave it connected as there is an o-ring that completes the seal.  Besides, that little tiny sensor hanging down in the middle of the tube costs over $300 so leave it alone!

      Caution - there will be two other hose connections and one electrical connection to the air intake tube that will need to be disconnected.  One of the hoses connects into the side of the larger diameter hose towards the front of the air intake tube.  This smaller diameter hose contains engine coolant and a small amount may leak out.  You may wish to cap this hose off to keep coolant from dripping out while working.

      TIP: This is a good place to take a digital photo to remember which hose goes where and which electrical connection goes where.  It really is practically impossible to mix them up but a photo or a hand drawn sketch comes in very handy when its time to put things back together.

    4. With the large air intake tube, air cleaner lid with the attached air flow sensor all being removed, you should be getting a good idea now about finally getting access to the plugs and wires.  I may have missed describing a few items or connections but if you've followed along this far, you should be able to figure out anything else that may hinder your access.  There's probably an wire connection or two that you may want to disconnect to get out of the way such as the large one towards the top left side of the throttle body.  The worst part is over.

    5. Work on only one cylinder at a time.  I suggest to begin at the upper right of the engine (the passenger side), which is cylinder #1.  Insert the boot puller tool down over the plug wire until the tool bottoms out on the metal boot (yes it goes in a long way) and then twist about 1/8 turn clockwise to grab the fins of the metal boot.  Pull straight out on the puller tool and the boot should slide off easily.  You will use this same technique on the remaining 5 cylinders.  The picture on the right side gives you a good idea of how the tool slides down and fits onto the metal boot of the spark plug wire.

      TIP - On this first cylinder, you can find that it is easy to see the exposed plug on the side.  However, this cylinder is probably the worst to get at because of the A/C lines, vacuum lines, and electrical connections that are right in the way.  Inserting the boot puller tool such as the one made by Schley with the solid T-handle on the end presents a problem because of the A/C lines that are in the way along with some vacuum lines, and some electrical connections.  You can temporarily remove the vacuum lines and electrical wires but the A/C pipes will prevent the T-handle tool from going in all the way.  Obviously the designers of the tool never worked on a engine with air conditioning.  It would be so nice if the T-handle were the type that would slide from side to side or would allow complete removal.  My fix was to hacksaw off one side of the t-handle.  Do whatever you have to do to make your tool work for you.  Other than the tight clearance in the lower 3 cylinders, this is the only one that has a lot of things in the way.

    6. Once you have to wire removed from the plug, your next task will be to remove that plug and replace it with a new one.  But before you do that, you need to make sure that any dirt or sand sitting at the bottom of the spark plug well is removed.  Otherwise, once the plug is out, that dirt and sand can fall into the cylinder and cause damage.  Some people have advocated using a can of compressed air and a length of flexible tubing to blow the dirt away.  Yes that method works well but you can eliminate the can of compressed air and just blow through the tubing.  Just poke the tubing down the plug well to almost all the way to the bottom.  Simply place your mouth over the open end and a couple of quick puffs of air will clean out the debris.  I recommend that you keep your eyes closed at the time because you'll be surprised just how much stuff comes out.

      TIP - Trying to keep the tubing straight might be a problem.  Just use a 12" long piece of stiff wire such as an old coat hanger and tape the tubing to the wire.

    7. Remove the spark plug using a standard 16mm (5/8") spark plug socket with rubber insert.  On the top three cylinders (numbers 1, 3, and 5) you will need at least a 12" extension and a 6" extension.  Make sure the 12" is at the end next to the plug.  It will just clear the top of the well which is why you need the additional 6" extension.  Once the plug is removed, make sure you don't drop anything down the spark plug well.  It is well advised to immediately install the new plug otherwise stuff a small rag into the well until you are ready to finish the job.  The picture on the right shows a new plug next to an old plug that went 50,000 miles without a misfire.

    8. Prepare the new spark plug by applying some anti-seize lubricant to the threads.  Now comes a little tricky part and that is getting the new plug started into the cylinder head without cross-threading it.  If you use a socket wrench, it is difficult to "feel" when the plug is starting to thread and difficult to tell when you are cross-threading it.  The solution is to use that same piece of 3/16" ID tubing that you used to blow the dirt out of the hole only this time you will slip the end of the tubing over the top terminal of the plug.  Then slip the plug with the tubing attached down into the plug well.  With a little guidance you'll find that it slides right into place.  Now start turning the tubing until you feel the plug threading into the hole.  If it goes only a 1/2 turn and gets very tight, then you're cross-threading. Back it up and starting turning again.  After a few tries, you'll feel the plug correctly start and just make sure you can turn it at least 3 or 4 complete turns with the tubing to make sure you have started in the thread correctly.  Now just pull on the tubing and it will slip off leaving the plug partially threaded into the hole.

      Auto purists and professional mechanics will sometimes disagree with me at this point.  Technically, before a new plug is installed, the threads should be cleaned using a spark plug thread chaser.  It uses a little grease applied in a small cavity right next to the cutting edge of the lead thread to capture and hold any dirt that is removed.  The reason for removing the dirt is to obtain a true torque reading when the new plug is tightened to its final torque setting.  If you have a spark plug thread chaser and the know-how to use it, then go ahead.  But do you really think a dealership would do this if they were working on your car?  And just how far off could the torque reading be if the threads are a little dirty?  I'll let you be the judge.

    9. With the plug started into the thread, now use your 16mm (5/8") spark plug socket WITHOUT the rubber insert and your long extensions to tighten up the plug.  You'll feel the "crush" of the washer start which means it time to quit with the hands and start to use a real torque wrench.  The reason for using the socket without the rubber insert is simple: once you had tightened up the plug, when you go to pull the sockets out of the hole, the socket will come apart where the extension attaches leaving your socket firmly attached to the spark plug deep down in the hole.  Use a torque wrench to bring the final tightening up to 18 ft/lbs.

      TIP - You may wish to invest in the more professional spark plug socket tool that is all one piece.  That eliminates the problem of the socket clinging to the plug while the extension piece pulls out all too easily.  The problem is that you would need to find one that is about 18" long so that it can reach the top three cylinders.  Another problem is that the lower three cylinders only need about 12" of extension so now you would need two such professional tools.

    10. Repeat the same process for changing the plugs on the next two cylinders at the top (cylinders 3 and 5).
    11. In order to gain access to the lower three spark plugs, you will need to tip the radiator forward to gain that needed clearance.  The top mounting of the radiator must be loosened to allow it to tip forward.  Before you do that, you need to remove the grill section with the VW emblem that is in front of the radiator.  There are two Phillips head screws, one at each end of the grill.  In the center of the VW emblem is another bolt, probably a socket head requiring a 5mm hex wrench.  With those three fasteners removed, lift the entire grill section out.  Now you can remove the two 10mm hex head bolts along the top on each side of the radiator.  The radiator can now be pushed forward from the top to put it in its tilted position.

      CAUTION - When you do tip the radiator forward, watch the rubber coolant hoses and the metal A/C pipes to make sure you don't pinch or dislodge any.  And when handling the electric fan assembly, be very gentle.  They are expensive to replace.

      You've probably heard about how the radiator tips forward to allow access to the plugs at the front of the engine.  Well, you've probably been mislead in thinking it tipped forward a lot and gave a clear shot at everything.  The truth is that it tips forward only four inches at the top.  But at the lower area where the plugs are at, you will gain only 2 inches!!  If you have a 12" long spark plug boot puller tool, there is no way that tool will fit in the confined area around those lower 3 plugs.

      TIP: After much discussion with those that thought they knew how (but had never really done it) and a few messages from those that actually had done it, here's the secret.  With the radiator tipped forward, remove the radiator fans.  They come out as one big assembly and it takes less than 5 minutes.  You now have sufficient clearance to access the plugs.  Do not even think about removing radiator hoses and A/C lines.  Do not even think about removing the lower grill panel that houses the light.  Remove the fans and all the problems go away.

    12. To remove the radiator fan assembly, disconnect the electrical connections before you remove any bolts.  You will probably have to crawl underneath to disconnect these two large electrical connectors.  The top portion of each connector that has its wires running up to the fan motor is held in place on a plastic U-shaped bracket.  There is a small half-moon shaped piece of metal that is folded over and has two crimps that hold it in place on the edges of the bracket.  Use a flat tip screwdriver to pry those clips off.  They will be re-used to re-attach the connectors when finished.  Once that metal clip is removed the connector will be hanging free and you can easy pull the two halves apart.  You will note that each connector has only a brown wire and a red wire.  Only a color-blind person could put them together backwards.  There is also a plastic cover about 10" long and looks sort of like an open mesh flat cover.  It does nothing other than cover over the wires where they come out of the fan and are directed towards the center and then down to the connections at the bottom.  This plastic cover will need to be opened up so that the wires are free to be moved out with the fans.  There are some small clips and tabs that hold it in place.

      CAUTION - You will find that this 10" long plastic cover has plastic clips that are very fragile.  If you pry up on one to allow it to slide over a tab so that you can remove it, you may find that the entire plastic clip will break off.  Don't panic.  This cover serves no other function than to keep the wires from flopping around in the breeze.  Even if you break all the plastic clips (not likely), just use some wire zip ties to hold the cover back in place.  Nobody will ever know and I won't tell.

      With the electrical connections free, remove the six 10mm bolts that hold the radiator fan assembly in place.  As you remove the last bolt, you should be holding onto the fan assembly.  Once free, just lift straight up and out.

      CAUTION - Handle the fan assembly with extreme care.  Set it in a safe place while you are finishing the work.  Do not pile any other objects on the fans.  They are very expensive so treat them with care.

    13. Once the radiator fans have been removed, you will find plenty of room to use the 12" long boot puller tool and your 12" extension for the spark plug socket.  Use the same procedure previously followed on the upper three cylinders on these three lower cylinders.  View the pictures below to see the access clearance gained by removing the fans and how easily the long boot removal tool can fit.

      Radiator fans removed.  Note the 2 U-shaped plastic brackets at the bottom center of the radiator.  These hold the electrical connectors in place. 12" long boot removal tool inserted in cyl #6 and still has plenty of clearance.  This would not have been possible with the fans in place.


    14. After replacing the three lower spark plugs and reattaching the spark plug wires, you should immediately replace the radiator fan assembly before something happens to it, i.e. somebody walks on it, etc.  Installation is just the reverse of removal.  Hold the assembly in place with one hand and start one of the 10mm bolts in place.  You will find that the plastic mount of the fan assembly snaps over the plastic mount of its frame.  Do not tighten the bolts until all are in place.  Once all the bolts have been tightened down, crawl back underneath and reattach the two electrical connectors (brown to brown and red to red).  Slide each connector in place on the plastic U-shaped bracket.  Push the metal clip in place.  You may need a small hammer to tap it all the way to the correct position.

      TIP- If the metal clip slides onto the bracket too easily, it will fall off from road vibration.  You may need to place the clip on a flat hard surface and hit it lightly with a hammer to SLIGHTLY close up the edge so that it gets more of a bite on the bracket.  Hit once with a hammer and then try it.  Do not hit it several times only to find out it is now too tight.

    15. Move the top of the radiator back into place and replace the four 10mm hex head bolts.  Replace the front grill assembly.  Before you replace the large black air intake tube, check for any other electrical connector, vacuum hose or coolant hose that you may have temporarily moved to gain access.  Reattach the battery cable if you removed it.  Once you are sure that you haven't missed anything, replace the black air intake tube along with all of its related hoses and connections.

    16. With all tools accounted for and rags and other items removed from the engine area, start the engine.  Let it idle for a few minutes.  Give it a little gas.  You should not see the Check Engine Light come on which would probably indicate a misfire on one or more of the cylinders if for some reason you failed to completely seat the spark plug wire and boot assembly.  Assuming that everything is OK, congratulate yourself on completing this job successfully.

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      Procedure for 24V VR6 (2001-2003)
      This procedure will be rewritten. The one that was here was for the 12 valve engine (AES), not the 24 valve (AXK)

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    Spark Plug Gap

    These measurements are all based on using the original specified spark plug.  Most manufacturers will indicate that their plugs are "pre-gapped" but its a good idea to check before installing.

  • 1995-1996 I-5 Engine ACU = 0.8mm (0.032 inches)

  • 1997-2000 VR6 140hp AES = 0.7mm (0.028 inches)*

  • 2001-2003 VR6 201hp AXK = 1.1mm (0.044 inches)

  • * These plugs are a "semi-surface ignition" spark plug and the method of measuring the gap is different than a convention plug.  The gap on these plugs refers to the distance between the projected insulator tip and the ground electrode.

     These are preset from the factory.  No need to gap.  The gap isn't between the center and ground electrodes.  This spark plug gap is the air gap between the backside of the ground electrode and the insulator.

    Technical Support Specialist

    Also note that these plugs have two ground electrodes but only one spark will be generated determined by the path with the least resistance.

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    Changing Ignition Wires

    In my opinion, its kind of a mistake to not change the spark plug wires at the same time as the spark plugs.  This is done only every 40,000 miles or longer and you have completed most of the work just getting to the plugs.  Changing the ignition wires at that point is very little additional labor.  Just make sure you buy a high quality brand such as the OEM product from a VW dealership or reputable online source.

    There is one minor problem in changing the wires on the I-5 and 12V version of the VR-6.  It is somewhat difficult to see the actual terminals on the ignition coil and most of the pulling the old ones off and putting the new ones on will be done relying mostly on "feel" instead of "sight".  There is one solution to this lack of sight problem and that involves removing the plastic battery box parts (see picture at right).  It looks very easy as all the parts just snap into one another but you'll find the main side section is pop-riveted in place at two spots.  I drilled out the pop-rivets so it wasn't really that much of a hassle but I don't think I gained any time by doing so.

    Unless you are totally familiar with the engine firing order and the correct numbering of the terminals, I strongly suggest that you replace only one wire at a time.  Almost all of the OEM quality wires will have the cylinder number marked on the wire.  Simply remove one old wire, and replace with a new wire of the same number.  You probably should hold the old one and the new one together just to confirm that they are the same length.

    The hardest problem is getting the old terminals connectors off because the nipple caps tend to stick in place.  Use a flat tipped screwdriver to help push the edge of the nipple cap off just slightly and you'll find everything removes much easier.

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    Additional Photos

    Note- All of the following photos depict certain actions while changing the spark plugs and ignition wires on a 2000 Rialta/EuroVan V6.  Some are taken only to provide documentation of hose and wire hookups so that re-assembly can be done without guesswork.  All photos are in high resolution which means your web browser may automatically resize the image so that it fits your screen resolution.  If it does resize the photo, you can click the resize gadget in the lower right of the photo to instruct your browser to view it in full resolution.

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    Page Updated: 8 October 2018