2000 Jeep Grand Cherokee spark plug replacement

This is a great vehicle. Even so it is a high...

iFixit Library 1999-2004 Jeep Grand Cherokee Moderate 1 hour Guide 15113

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Guide overview

Before you begin

This is a great vehicle. Even so it is a high mileage SUV (235,000 miles), junior still uses it as a daily driver. The interval for changing the spark plugs is listed as every 30,000 miles. It is a relatively straight forward task and does only require basic metric hand tools. The spark plugs used for this model are Autolite XP985, pre-gapped at 0.89 mm (.035 in.).

Step 1

Repair step

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The 4.0L 6–cylinder engine uses a one-piece coil rail containing three independent coils. Located on the right hand side (passenger side) of the engine.
The one-piece coil bolts directly to the cylinder head with 4 13mm hex bolt (M8X50). 3 of the bolts are immediately visible.
The fourth one is somewhat hidden in the back, under the coolant lines for the heater. The hoses can easily be moved out of the way.

Step 2

Repair step

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Start removing the 13mm bolts from the coil rail. Use an extension will make it easier to clear the radiator hoses and throttle cables.
Use a smaller extension to remove the 4th bolt in the back of the rail.
All 4 bolts are identical in size and need not to be separated.

Step 3

Repair step

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With all 4 bolts removed, the rail should easily pull off the spark plugs. One electrical connector (located at the rear end of the coil rail) is used for all three coils. It is not necessary to totally remove the rail for a spark plug change.
Rubber boots seal the secondary terminal ends of the coils to the top of all 6 spark plugs.
Use a 5/8inch spark plug socket and extension to remove the spark plug. Again, the ignition rail can be easily moved out of the way.

Step 4

Repair step

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Continue to remove all spark plugs.
To remove the last spark plug in the rear, use a longer extension. Always ensure that the socket is properly seated on the spark plug.
With all spark plugs removed, it is clearly visible that these plugs were in definite need to be replaced.