GrandCaravan 2008

Spark Plugs

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Inspection



Special care should be taken when installing spark plugs into the cylinder head spark plug wells. Be sure the plugs do not drop into the plug wells as electrodes can be damaged.

Always tighten spark plugs to the specified torque. Over-tightening can cause distortion resulting in a change in the spark plug gap or a cracked porcelain insulator. Proper torque is especially important in the case of aluminum cylinder heads.

When replacing the spark plug and ignition coil cables, route the cables correctly and secure them in the appropriate retainers. Failure to route the cables properly can cause the radio to reproduce ignition noise. It could also cause cross ignition of the spark plugs and/or cause a short circuit in the cables to a ground.

Chipped Electrode Insulator

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

A chipped electrode insulator usually results from bending the center electrode while adjusting the spark plug electrode gap. Under certain conditions, severe detonation can also separate the insulator from the center electrode. Spark plugs with this condition must be replaced.

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Fig. Chipped insulation (3) around center electrode (2) demands spark plug replacement

Cold Fouling/Carbon Fouling

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

Cold fouling is sometimes referred to as carbon fouling. The deposits that cause cold fouling are basically carbon. A dry, black deposit on one or two plugs in a set may be caused by sticking valves or defective spark plug cables. Cold (carbon) fouling of the entire set of spark plugs may be caused by a clogged air cleaner element or repeated short operating times (short trips).

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Fig. Normal operation with tan or light gray deposits (1). Cold fouling/carbon fouling with dry, black deposits (2), (3)

Electrode Gap Bridging

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

Electrode gap bridging may be traced to loose deposits in the combustion chamber. These deposits accumulate on the spark plugs during continuous stop-and-go driving. When the engine is suddenly subjected to a high torque load, deposits partially liquefy and bridge the gap between electrodes. This short circuits the electrodes. Spark plugs with electrode gap bridging can be cleaned using standard procedures.

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Fig. Deposits (2) bridging gap between ground electrode (1) and center electrode (3)

Normal Operation

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

Under normal operating conditions, there may be deposits present on the spark plug that are light tan or slightly gray in color. This is evident with most grades of commercial gasoline. A good spark plug should have no evidence of electrode burning.

Some fuel refiners in several areas of the United States have introduced a manganese additive (MMT) for unleaded fuel. During combustion, fuel with MMT causes the entire tip of the spark plug to be coated with a rust colored deposit. This rust color can be misdiagnosed as being caused by coolant in the combustion chamber. Spark plug performance may be affected by MMT deposits.

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Fig. Normal operation with tan or light gray deposits (1). Cold fouling/carbon fouling with dry, black deposits (2), (3)

Oil or Ash Encrusted

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

If one or more spark plugs are oil or oil ash encrusted, evaluate engine condition for the cause of oil entry into that particular combustion chamber.

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Fig. Oil or ash encrustation on electrodes

Pre-Ignition Damage

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

Preignition damage is usually caused by excessive combustion chamber temperature. The center electrode dissolves first and the ground electrode dissolves somewhat later. Insulators appear relatively deposit free. Determine if the spark plug has the correct heat range rating for the engine. Determine if the ignition timing is over advanced or if other operating conditions are causing engine overheating. The heat range rating refers to the operating temperature of a particular type of spark plug. Spark plugs are designed to operate within specific temperature ranges which depend upon the thickness and length of the center electrodes and porcelain insulator.

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Fig. Ground (1) and center (2) electrode dissolving

Scavenger Deposits

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

Fuel scavenger deposits may be either white or yellow. They may appear to be harmful, but this is a normal condition caused by chemical additives in certain fuels. These additives are designed to change the chemical nature of deposits and decrease spark plug misfire tendencies. Notice that accumulation on the ground electrode and shell area may be heavy, but the deposits are easily removed. Spark plugs with scavenger deposits can be considered normal in condition and can be cleaned using standard procedures.

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Fig. White or yellow deposits form on ground (1) or center (2) electrodes

Spark Plug Overheating

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

Overheating is indicated by a white or gray center electrode insulator that also appears blistered. The increase in electrode gap will be considerably in excess of 0.001 inch per 2,000 miles of operation. This suggests that a plug with a cooler heat range rating should be used. Over advanced ignition timing, detonation, and cooling system malfunctions can also cause spark plug overheating.

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Fig. Blistered white or gray center electrode insulator (1)

Wet Fouling Or Gas Fouling

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

A spark plug coated with excessive wet fuel or oil is wet fouled. In older engines, worn piston rings, leaking valve guide seals or excessive cylinder wear can cause wet fouling. In new or recently overhauled engines, wet fouling may occur before break-in (normal oil control) is achieved. This condition can usually be resolved by cleaning and reinstalling the fouled plugs.

Removal & Installation



3.3L & 3.8L Engines

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

When replacing the spark plugs and spark plug cables, route the cables correctly and secure them in the appropriate retainers. Failure to route the cables properly can cause the radio to reproduce ignition noise, cross ignition of the spark plugs, or short circuit the cables to ground.

When removing spark plugs, work on one at a time. Don't start by removing the plug wires all at once, because, unless they are numbered, they may become mixed up. Use tape to number the wires as necessary.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. If the vehicle has been run recently, allow the engine to thoroughly cool.
    NOTE
    Always remove cables by grasping at the boot, rotating the boot 1 / 2 turn, and pulling straight back in a steady motion.

  4.  
  5. Prior to removing the spark plug, spray compressed air around the spark plug hole and the area around the spark plug.
  6.  
  7. Remove the spark plug using a quality socket with a foam or rubber insert.
  8.  
  9. Inspect the spark plug condition.
  10.  

To install:

  1. Apply a small amount of anti-seize compound to the threads of each spark plug.
  2.  
  3. Check and adjust the spark plug gap according to specifications.
    NOTE
    Start each spark plug by hand to avoid cross-threading and plug damage; use a quality socket with a rubber insert and start each spark plug into the cylinder head by hand.

  4.  
  5. Install the spark plug and tighten to 13 ft. lbs. (18 Nm).
  6.  
  7. Install the ignition cables over the spark plugs. An audible click noise can be heard and felt when the ignition cable is properly attached to the spark plug.
  8.  

4.0L Engine

Specific to:

Chrysler Town & Country 2008-2009

Dodge Grand Caravan 2008-2009

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect and isolate the negative battery cable.
  4.  
  5. Remove the engine cover.
  6.  
  7. Remove the intake manifold. Refer to Intake Manifold, removal & installation.
    NOTE
    Prior to removing the ignition coil, spray compressed air around the coil top to make sure no debris drops into the spark plug tube.

  8.  
  9. Remove the ignition coil assembly. Refer to Ignition Coil Pack, removal & installation.
    NOTE
    Prior to loosening the spark plug, use compressed air to blow out any debris that might be in the spark plug tube.

  10.  
  11. Remove the spark plug using a quality socket with a foam or rubber insert.
  12.  

To install:


WARNING
Start each spark plug by hand to avoid cross-threading and plug damage; use a quality socket with a rubber insert and start each spark plug into the cylinder head by hand.

  1. Tighten the spark plugs to 20 ft. lbs. (27 Nm).
  2.  
  3. Install ignition coil assembly. Refer to Ignition Coil Pack, removal & installation.
  4.  
  5. Install the intake manifold. Refer to Intake Manifold, removal & installation.
  6.  
  7. Install the engine cover.
  8.  
  9. Connect the negative battery cable and tighten the nut to 45 inch lbs. (5 Nm).
  10.  

 
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