How to Change the Spark Plugs on a 2004 Chevrolet Cavalierby Scott WhitneyUpdated November 07, 2017
Items you will need
5/8 spark plug socket
Straight socket extension
Silicone spark plug boot compound
Spark plug gap gauge
Properly gapped spark plugs help ensure smooth engine operation and fuel efficiency. The 2004 Chevrolet Cavalier Owner's Manual suggests changing spark plugs every 100,000 miles. They also should be one of the parts checked when gas mileage starts to drop.
Removing the Plugs
Remove the negative battery cable to prevent electrical power to the engine.
If the engine is a 2.2 liter, you will see the spark plug cables and can gently twist them to free them from the plugs. If the engine is a 2.4 liter, unplug the coil connector and remove the four retaining bolts, and remove the coil from the engine. The spark plug cables will be visible; gently twist them to free them from the plugs.
Clean the spark plug well to keep any debris from falling into the cylinder when the plugs are removed. Canned air works well, but if it is not available, a brush or other cleaning equipment may be used.
Use a spark plug socket with the rubber insert to remove the plug.
Installing the Plugs
Inspect the spark plug boot and wire for breaks or tears. Replace the spark plug wire if any problems are found.
Check the gap on the new plugs with a feeler gauge by inserting the proper size wire measure between the electrodes with only a slight drag. The gap size will be found in the owner's manual.
Seat the new spark plugs in the cylinder head by hand. If resistance is felt before the plug is seated, back the plug out and start again to prevent cross threading, which can cause damage to the cylinder head and the spark plug.
Tighten the plug to the manufacturer's specifications once it is seated.
Apply a silicon spark plug connection compound to the boot and plug before re-installing the spark plug wire. Re-install the coil on the 2.4 litre engine.
Remove and replace one plug at a time, finishing one before starting the next, in order to keep track of the order of the wires.
A spark plug boot should be used to seat the new plugs if they cannot be set by hand.
Allow the engine time to cool if it has been running recently so you don't get burned.
Use only a straight extension bar on the socket to avoid sheer pressure, which could damage the threads on the cylinder head or the spark plug.
- old spark plugs image by Rog999 from Fotolia.com