How to Replace the Spark Plugs on a 2003 Forester
As the owner of a 2003 Subaru Forester, changing your own spark plugs is an easy and affordable way to keep your vehicle running smoothly. Subaru recommends changing your spark plugs every 60,000 to 100,000 miles, but many experts recommend changing them every year or two for maximum performance. As spark plugs provide the spark which ignites the fuel in each cylinder, a reliable and powerful spark is a necessary component for a well-maintained engine.
Other People Are Reading
Things You'll Need
- Socket wrench
- Spark plug socket or 5/8ths socket
- Anti-seize compound
- Socket extender
- New spark plugs
- Screwdriver
- Owner's manual
Instructions
-
-
1
Locate the spark plugs. On the 2003 Subaru Forester, the spark plugs are on either side of the engine, directly in the center of the hood. It may be helpful to remove the air filter box on the driver's side before beginning to work on the spark plugs. The air filter box can be removed with a screwdriver.
-
2
Remove one spark plug wire by grabbing the boot of the wire, which is the thicker end of the wire that connects with the spark plug itself. Pulling directly away from the spark plug chamber should disconnect the wire from the spark plug with a loud pop. Be careful to pull on the wire boot, rather than the wire itself, as doing so may cause damage to the wire.
-
-
3
Insert your spark plug socket on the end of the socket extender. Rotate counterclockwise until the socket locks onto the spark plug. Be careful not to rotate the spark plug until this occurs, or stripping of the spark plug itself may result. Turn the spark plug counterclockwise until it can be easily pulled out of its chamber.
-
4
Spread a small amount of anti-seize compound around the screw threads of the new spark plug. This will stop the spark plug from permanently seizing to the inside of the spark plug chamber due to the heat of the engine.
-
5
Insert the new spark plug into the chamber on the end of the socket wrench socket. Be careful not to hit it against the wall of the chamber. Rotate the spark plug clockwise until it settles in place, then rotate it until you encounter serious resistance. At this point, rotate an additional 1/8th turn to correctly add enough torque to the spark plug and ensure it has a good connection.
-
6
Reconnect the spark plug wire by pushing the wire boot into the spark plug chamber until you hear the loud pop of the wire snapping onto the spark plug itself. Repeat these steps for each additional spark plug, working with just one wire and plug at a time to avoid crossing the spark plug wires, which can cause serious damage to the engine.
-
1
Tips & Warnings
Examine the spark plugs you've removed. If there is any damage beyond blackening, consult a repair shop as there may be a more serious problem in the engine or ignition system.
Never replace spark plugs if the engine is warm or running. Always allow the engine to cool for a few hours before working with the spark plugs.
References
- Photo Credit engine image by goce risteski from Fotolia.com
