Revolutionize Your Subaru Forester’s Performance: How to Change Spark Plug Subaru Forester

Are you experiencing a rough idle, sluggish acceleration, or a decrease in fuel efficiency in your Subaru Forester? These could be signs that your spark plugs need replacing. While it may seem daunting, changing spark plugs on a Subaru Forester is a relatively straightforward DIY task. This guide will walk you through the process step-by-step, empowering you to tackle this essential maintenance on your own.

Why Change Spark Plugs?

Spark plugs are crucial components in your car’s engine, responsible for igniting the air-fuel mixture that powers your vehicle. Over time, spark plugs wear down, leading to a decrease in performance. Here are some telltale signs that your spark plugs might need replacing:

• Rough idle: If your engine idles unevenly or shakes, it could indicate a faulty spark plug.
• Sluggish acceleration: A loss of power when accelerating could also be caused by worn-out spark plugs.
• Decreased fuel efficiency: Spark plugs directly impact fuel combustion efficiency. If your car is using more fuel than usual, it might be time for a spark plug change.
• Misfires: Misfires can cause a jerking sensation while driving and are a common indicator of a failing spark plug.
• Check engine light: A check engine light can illuminate due to various reasons, including a faulty spark plug.

Tools and Materials You’ll Need

Before you start, gather the necessary tools and materials:

• New spark plugs: Refer to your Subaru Forester owner’s manual for the correct spark plug type and gap specifications.
• Socket wrench: The size of the socket wrench needed will depend on the spark plug size. Most Subaru Foresters use a 5/8-inch socket.
• Torque wrench: This is crucial for tightening the spark plugs to the correct specification, preventing damage to the threads.
• Spark plug gap tool: Used to adjust the gap of the new spark plugs to the manufacturer’s specifications.
• Ratchet: A standard ratchet will be needed to turn the socket wrench.
• Extension: An extension may be required to reach the spark plugs, depending on the engine configuration.
• Gloves: Protect your hands from dirt and grime.
• Safety glasses: Always wear eye protection when working on your vehicle.

Step-by-Step Guide to Changing Spark Plugs

Now, let’s get down to the actual process:

1. Disconnect the Battery:

• Locate the battery in the engine compartment.
• Disconnect the negative (-) terminal first, then the positive (+) terminal. This prevents any electrical shock hazards.

2. Locate the Spark Plugs:

• Open the hood of your Subaru Forester.
• The spark plugs are typically located on the top of the engine, near the center.
• Refer to your owner’s manual or an online diagram for the exact location on your specific model.

3. Remove the Spark Plug Wires (if applicable):

• Some Subaru Forester models have spark plug wires, while others have coil packs.
• If your model has spark plug wires, carefully disconnect them from the spark plugs.
• Remember to note the order of the wires to ensure proper reconnection later.

4. Remove the Spark Plugs:

• Use the socket wrench and ratchet to loosen the spark plugs.
• Turn the socket counterclockwise to loosen the spark plugs.
• Once loosened, remove the spark plugs by hand.

5. Inspect the Old Spark Plugs:

• Examine the old spark plugs for signs of wear or damage.
• Look for excessive wear on the electrodes, carbon buildup, or cracks.
• These signs indicate that the spark plugs were working properly.

6. Install the New Spark Plugs:

• Before installing the new spark plugs, use the spark plug gap tool to ensure they are set to the correct gap specification.
• Thread the new spark plugs into the spark plug holes by hand until they are snug.
• Use the torque wrench to tighten the spark plugs to the specified torque.
• Refer to your owner’s manual for the correct torque setting.

7. Reconnect the Spark Plug Wires (if applicable):

• If your model has spark plug wires, reconnect them to the spark plugs in the correct order.

8. Reconnect the Battery:

• Connect the positive (+) terminal first, then the negative (-) terminal.

9. Start the Engine:

• Start the engine and listen for any unusual noises or misfires.
• If everything seems normal, let the engine warm up for a few minutes.

10. Check for Leaks:

• After the engine has warmed up, check for any leaks around the spark plugs.

Tips for Success

• Use a torque wrench: This is absolutely essential to prevent over-tightening and damaging the spark plug threads.
• Clean the spark plug holes: Before installing the new spark plugs, use a brush or compressed air to remove any dirt or debris from the spark plug holes.
• Don’t overtighten: Overtightening the spark plugs can damage the threads and cause leaks.
• Use the correct spark plugs: Using the wrong spark plugs can damage your engine. Refer to your owner’s manual for the correct spark plug type and gap specifications.

Beyond the Basics: Understanding Spark Plug Types

Not all spark plugs are created equal. Subaru Foresters utilize different types of spark plugs, each with its own advantages and disadvantages. Here’s a brief breakdown:

• Copper Spark Plugs: These are the most affordable option and offer decent performance for standard driving conditions.
• Platinum Spark Plugs: Platinum spark plugs feature a platinum electrode, which is more durable and resistant to wear than copper. This translates to a longer service life.
• Iridium Spark Plugs: Iridium spark plugs are the most durable and offer the longest service life. They are also known for their superior performance at high temperatures.

The Final Touch: A Clean Engine Bay

After successfully changing your spark plugs, take a moment to clean up the engine bay. This will not only make your engine look great, but it will also help you spot any potential leaks or problems in the future.

Final Thoughts: A Job Well Done

Congratulations! You’ve successfully changed the spark plugs on your Subaru Forester. By following this guide, you’ve saved money and gained valuable experience in maintaining your vehicle. Remember to keep an eye on your spark plugs and replace them as needed.

Questions We Hear a Lot

Q: How often should I change my spark plugs?

A: The recommended service interval for spark plugs varies depending on the type of spark plug used. Copper spark plugs typically need replacement every 30,000 miles, while platinum and iridium spark plugs can last up to 100,000 miles. Always refer to your Subaru Forester‘s owner’s manual for specific recommendations.

Q: Can I change the spark plugs myself?

A: Yes, changing spark plugs is a relatively simple DIY task. However, if you are uncomfortable working on your vehicle, it’s best to take it to a qualified mechanic.

Q: What happens if I don’t change my spark plugs?

A: Failing to change your spark plugs can lead to a number of problems, including decreased fuel efficiency, rough idling, sluggish acceleration, and engine misfires. In severe cases, it can even damage your engine.

Q: What if I accidentally cross-thread a spark plug?

A: If you cross-thread a spark plug, it’s important to stop immediately and seek professional help. Trying to force the spark plug in can damage the threads and lead to serious engine problems.