Alero, Grand Am 1999-2005

Spark Plugs

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Inspection & Gapping



Check the plugs for deposits and wear. If they are not going to be replaced, clean the plugs thoroughly. Remember that any kind of deposit will decrease the efficiency of the plug. Plugs can be cleaned on a spark plug cleaning machine, which can sometimes be found in service stations, or you can do an acceptable job of cleaning with a stiff brush. If the plugs are cleaned, the electrodes must be filed flat. Use an ignition points file, not an emery board or the like, which will leave deposits. The electrodes must be filed perfectly flat with sharp edges; rounded edges reduce the spark plug voltage by as much as 50%.

Check spark plug gap before installation. The ground electrode (the L-shaped one connected to the body of the plug) must be parallel to the center electrode and the specified size wire gauge (please refer to the Tune-Up Specifications chart for details) must pass between the electrodes with a slight drag.


NOTE
NEVER adjust the gap on a used platinum type spark plug.

Always check the gap on new plugs as they are not always set correctly at the factory. Do not use a flat feeler gauge when measuring the gap on a used plug, because the reading may be inaccurate. A round-wire type gapping tool is the best way to check the gap. The correct gauge should pass through the electrode gap with a slight drag. If you're in doubt, try one size smaller and one larger. The smaller gauge should go through easily, while the larger one shouldn't go through at all. Wire gapping tools usually have a bending tool attached. Use that to adjust the side electrode until the proper distance is obtained. Absolutely never attempt to bend the center electrode. Also, be careful not to bend the side electrode too far or too often as it may weaken and break off within the engine, requiring removal of the cylinder head to retrieve it.

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Fig. Inspect the spark plug to determine engine running conditions



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Fig. A variety of tools and gauges are needed for spark plug service



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Fig. Checking the spark plug gap with a feeler gauge



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Fig. Adjusting the spark plug gap



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Fig. If the standard plug is in good condition, the electrode may be filed flat-WARNING: do not file platinum plugs

Removal & Installation



2.2L Engine

NOTE
This engine has aluminum cylinder heads. Do not remove the spark plugs from a hot engine, allow it to cool first. Removing the spark plugs from a hot engine may cause spark plug thread damage or cylinder head damage.

  1. Remove the ignition coil housing.
    NOTE
    Remove any water and debris from the spark plug holes before spark plug removal with compressed air.

  2.  
  3. Remove the spark plugs with a spark plug socket.
  4.  
  5. Inspect the spark plugs.
  6.  

To install:

  1. Gap the spark plug, using round wire type spark plug gap gauge. Adjust the spark plug gap to 0.045 in. (1.14mm).
    WARNING
     DO NOT coat the spark plugs with anti seize compound. Over torquing could occur and damage to the cylinder head threads may result.

  2.  
  3. Install the spark plugs with a spark plug socket. Tighten to 15 ft. lbs. (20 Nm).
  4.  
  5. Install the ignition coil housing.
  6.  

2.4L Engine

The spark plugs on this engine are located under the ignition coil and module assembly. To gain access to the spark plugs, the coil and module assembly must be removed. On the 2.4L (VIN T) engines, the spark plugs are platinum and require replacement every 100,000 miles (160,900 km) or 60 months which ever comes first.


NOTE
To avoid engine damage, do not remove the spark plugs when the engine is warm. When you're removing spark plugs, work on only one at a time. Don't start by removing the plug wires all at once, because unless you number them, they may become mixed up. Take a minute before you begin and number the wires with tape. The best location for numbering is as near as possible to the spark plug boot.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the 4 bolts retaining the Electronic Ignition (EI) coil/module/cover assembly (depending upon vehicle application), then detach the electrical connector. Remove the assembly by pulling it straight up away from the engine.

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    Fig. To remove the cover, unfasten the four bolts, then pull the assembly straight up from the engine

  4.  
  5. If the connector(s) sticks to the spark plug, use spark plug connector removing tool J-36011 or equivalent, and a twisting motion to detach the connector(s) from the plugs.

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    Fig. If any of the connectors stick to the spark plug, using this tool and a twisting motion will free the connectors from the spark plugs



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    Fig. Remove the four spark plug rubber covers

  6.  
  7. Clean any dirt away from the spark plug recess area.
  8.  
  9. Remove the spark plug using the proper size socket, extensions and universal joints, as necessary. Hold the socket or the extension close to the plug with your free hand, as this will help lessen the possibility of applying a shear force which might snap the plug in half.

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    Fig. Use a spark plug socket and remove each plug one at a time

  10.  

To install:

  1. Lubricate the threads lightly with an anti-seize compound, then start the four spark plugs by hand. Tighten the plugs to 14 ft. lbs. (19 Nm).
  2.  
  3. If removed, install any the plug boot connectors that may have stuck to a spark plug to the EI assembly.
    NOTE
    Check to make sure the spring terminal is inside the boot.

  4.  
  5. Install the EI coil/module/cover assembly to the engine, while carefully aligning the boots with the spark plug terminals, by pushing the assembly straight down.
  6.  
  7. Apply Loctite®thread locking compound, or equivalent to the cover bolts. Install the bolts and tighten to 16 ft. lbs. (22 Nm).
  8.  
  9. If removed, engage the ignition cover electrical connectors.
  10.  
  11. Connect the negative battery cable.
  12.  

3.1L Engine
  1. Disconnect the negative battery cable, and if the vehicle has been run recently, allow the engine to thoroughly cool.
  2.  
  3. On some models it may be necessary to remove the air cleaner or any other components hindering spark plug removal.
  4.  
  5. Carefully twist the spark plug wire boot to loosen it, then pull upward and remove the boot from the plug. Be sure to pull on the boot and not on the wire, otherwise the connector located inside the boot may become separated.

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    Fig. Remove the spark plug wire by twisting the boot 1/2turn, then pulling up

  6.  
  7. Using compressed air, blow any water or debris from the spark plug well to assure that no harmful contaminants are allowed to enter the combustion chamber when the spark plug is removed. If compressed air is not available, use a rag or a brush to clean the area.
    NOTE
    Remove the spark plugs when the engine is cold, if possible, to prevent damage to the threads. If removal of the plugs is difficult, apply a few drops of penetrating oil or silicone spray to the area around the base of the plug, and allow it a few minutes to work.

  8.  
  9. Using a spark plug socket that is equipped with a rubber insert to properly hold the plug, turn the spark plug counterclockwise to loosen and remove the spark plug from the bore.
    WARNING
    Be sure not to use a flexible extension on the socket. Use of a flexible extension may allow a shear force to be applied to the plug. A shear force could break the plug off in the cylinder head, leading to costly and frustrating repairs.



    Click image to see an enlarged view

    Fig. Using the proper size socket and ratchet combination, remove the spark plugs

  10.  

To install:

  1. Inspect the spark plug boot for tears or damage. If a damaged boot is found, the spark plug wire must be replaced.
  2.  
  3. Using a wire feeler gauge, check and adjust the spark plug gap. When using a gauge, the proper size should pass between the electrodes with a slight drag. The next larger size should not be able to pass while the next smaller size should pass freely.
    NOTE
    The spark plug gap is sometimes embossed on the valve cover.

  4.  
  5. Carefully thread the plug into the bore by hand. If resistance is felt before the plug is almost completely threaded, back the plug out and begin threading again. In small, hard to reach areas, an old spark plug wire and boot could be used as a threading tool. The boot will hold the plug while you twist the end of the wire and the wire is supple enough to twist before it would allow the plug to crossthread.
    WARNING
    Do not use the spark plug socket to thread the plugs. Always carefully thread the plug by hand or using an old plug wire to prevent the possibility of crossthreading and damaging the cylinder head bore.

  6.  
  7. Carefully tighten the spark plug. If the plug you are installing is equipped with a crush washer, seat the plug, then tighten about 1 / 4 turn to crush the washer. If you are installing a tapered seat plug, tighten the plug to 13 ft. lbs. (18 Nm)
  8.  
  9. Apply a small amount of silicone dielectric compound to the end of the spark plug lead or inside the spark plug boot to prevent sticking, then install the boot to the spark plug and push until it clicks into place. The click may be felt or heard, then gently pull back on the boot to assure proper contact.
  10.  

3.4L Engine

Observe the following service precautions:



Allow the engine to cool before removing the spark plugs. Attempting to remove spark plugs from a hot engine can cause the spark plugs to seize. This can damage the cylinder head threads.
 
Clean the spark plug recess area before removing the spark plug. Failure to do so can result in engine damage due to dirt or foreign material entering the cylinder head, or in contamination of the cylinder head threads. Contaminated threads may prevent proper seating of the new spark plug.
 
Use only the spark plugs specified for use in the vehicle. Do not install spark plugs that are either hotter or colder than those specified for the vehicle. Installing spark plugs of another type can severely damage the engine.
 

  1. Turn OFF the ignition.
  2.  
  3. If you are replacing the engine right bank (rear) spark plugs, perform the following steps:
    1. Remove the windshield wiper module cover.
    2.  
    3. Rotate the engine for service access.
    4.  

  4.  
  5. Remove the spark plug wires from the spark plugs.
  6.  
  7. Remove the spark plugs from the engine.
  8.  

To install:


NOTE
It is important to check the gap of all new and reconditioned spark plugs before installation. Pre-set gaps may have changed during handling. Use a round wire feeler gauge to be sure of an accurate check, particularly on used plugs. Installing plugs with the wrong gap can cause poor engine performance and may even damage the engine.

  1. Gap the spark plugs to 0.060 in. (1.52mm).
    NOTE
    Be sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.

  2.  
  3. Install the spark plugs to the engine and tighten 11 ft. lbs. (15 Nm).
  4.  
  5. Install the spark plug wires to the spark plugs.
  6.  
  7. If you are replacing the engine right bank (rear) spark plugs, perform the following steps:
    1. Return the engine to the proper position.
    2.  
    3. Install the windshield wiper module cover.
    4.  

  8.  

 
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