Quick Overview
- You’ll need a socket wrench set with a 5/8-inch socket to remove and install the spark plugs.
- The spark plugs in your 2019 Highlander are located on the top of the engine, under the valve cover.
- If the spark plug is covered in carbon or oil, it indicates a problem with the engine that needs to be addressed.
Are you experiencing a rough idle, decreased fuel efficiency, or misfires in your 2019 Toyota Highlander? These could be signs of worn-out spark plugs, and replacing them is a relatively simple DIY project that can restore your vehicle’s performance. This comprehensive guide will walk you through the process of changing spark plugs on your 2019 Highlander, providing clear instructions and helpful tips to ensure a smooth and successful repair.
Gathering Your Tools and Supplies
Before you dive into changing your spark plugs, make sure you have all the necessary tools and supplies:
- New spark plugs: Refer to your owner’s manual or consult a trusted auto parts store to determine the correct spark plugs for your 2019 Highlander.
- Socket wrench set: You’ll need a socket wrench set with a 5/8-inch socket to remove and install the spark plugs.
- Torque wrench: A torque wrench is essential for tightening the spark plugs to the proper specifications.
- Ratchet: A ratchet will make it easier to turn the socket wrench.
- Extension bar: An extension bar will provide extra reach for accessing the spark plugs.
- Spark plug gap tool: This tool helps you adjust the gap of the new spark plugs to the correct measurement.
- Gloves: Wear gloves to protect your hands from dirt and grease.
- Safety glasses: Always wear safety glasses to protect your eyes from debris.
- Shop towels: Keep shop towels handy for cleaning up any spills or messes.
Understanding the Importance of Spark Plugs
Spark plugs play a crucial role in your Highlander’s combustion process. They ignite the air-fuel mixture inside the cylinders, creating the power that drives your vehicle. Over time, spark plugs can wear down, leading to:
- Reduced engine performance: Worn-out spark plugs can cause misfires, resulting in a decrease in power and acceleration.
- Rough idle: Misfires can also lead to a rough idle, making your vehicle shake or vibrate.
- Decreased fuel efficiency: When spark plugs are worn, your engine may not burn fuel efficiently, leading to lower gas mileage.
- Increased emissions: Misfires can also result in increased emissions, harming the environment.
Locating the Spark Plugs
The spark plugs in your 2019 Highlander are located on the top of the engine, under the valve cover. You’ll need to remove the valve cover to access the spark plugs.
Step 1: Disconnect the Battery
Before you begin working on your vehicle, it’s essential to disconnect the battery to prevent electrical shocks. Locate the battery in the engine compartment and disconnect the negative terminal (usually black) first, followed by the positive terminal (usually red).
Step 2: Remove the Valve Cover
The valve cover is held in place by several bolts. Using a socket wrench, loosen and remove these bolts. Once the bolts are removed, carefully lift the valve cover off the engine.
Step 3: Locate the Spark Plugs
Once the valve cover is removed, you’ll see the spark plugs. Each spark plug is connected to a spark plug wire.
Replacing the Spark Plugs
Step 1: Disconnect the Spark Plug Wires
Carefully disconnect each spark plug wire from the spark plug. Pull on the wire boot, not the wire itself, to prevent damage.
Step 2: Remove the Old Spark Plugs
Using a 5/8-inch socket wrench, loosen and remove the old spark plugs. Be careful not to cross-thread the socket wrench.
Step 3: Inspect the Old Spark Plugs
Inspect the old spark plugs for signs of wear, such as:
- Electrode wear: The electrode should be sharp and pointed. If it’s rounded or worn down, it’s time for a replacement.
- Gap wear: The gap between the electrodes should be within the manufacturer’s specifications. If it’s too wide or too narrow, it can affect engine performance.
- Fouling: If the spark plug is covered in carbon or oil, it indicates a problem with the engine that needs to be addressed.
Step 4: Install the New Spark Plugs
Before installing the new spark plugs, make sure they are gapped correctly using a spark plug gap tool. Once the new spark plugs are gapped, screw them into the cylinder head by hand until they are snug.
Step 5: Tighten the Spark Plugs
Using a torque wrench, tighten the spark plugs to the specified torque. The torque specification for your 2019 Highlander can be found in your owner’s manual or online.
Step 6: Reconnect the Spark Plug Wires
Carefully reconnect the spark plug wires to the new spark plugs. Make sure the wires are securely connected and that there are no loose connections.
Step 7: Reinstall the Valve Cover
Align the valve cover with the engine and carefully lower it into place. Replace the bolts and tighten them to the specified torque.
Step 8: Connect the Battery
Reconnect the battery terminals in reverse order, starting with the positive terminal (red) and then the negative terminal (black).
Checking for Proper Operation
After replacing the spark plugs, start your 2019 Highlander and let it run for a few minutes. Listen for any unusual sounds or vibrations. If everything seems to be running smoothly, you’ve successfully replaced your spark plugs.
Final Thoughts: Beyond the Spark Plugs
While changing spark plugs is a relatively straightforward task, it’s crucial to remember that this is just one aspect of maintaining your vehicle’s overall health. Regular maintenance, including oil changes, air filter replacements, and tire rotations, is essential for ensuring optimal performance and longevity.
Information You Need to Know
Q: How often should I change my spark plugs?
A: The recommended replacement interval for spark plugs varies depending on the type of spark plugs and your driving habits. However, generally, spark plugs should be replaced every 30,000 to 100,000 miles. Refer to your owner’s manual for specific recommendations.
Q: Can I use different spark plugs than the ones recommended by Toyota?
A: It’s generally advisable to use the spark plugs specified by Toyota for your 2019 Highlander. Using different spark plugs could potentially affect engine performance and warranty coverage.
Q: What if I notice a problem after replacing the spark plugs?
A: If you experience any issues after replacing the spark plugs, it’s best to consult a qualified mechanic to diagnose and resolve the problem.
Q: Can I change the spark plugs myself, or should I take it to a mechanic?
A: Changing spark plugs is a relatively simple DIY project, but it requires some basic mechanical knowledge and tools. If you’re not comfortable working on your vehicle, it’s best to take it to a mechanic.
Q: How long does it typically take to change spark plugs?
A: The time it takes to change spark plugs can vary depending on your experience and the specific vehicle. However, it typically takes between 30 minutes to an hour for a skilled DIYer.