How to replace glow plugs?

Glow plugs generally have a very long life, around 80,000 km. If you notice white smoke when starting, it's a good sign that they need to be replaced soon. If starting is difficult, there's also a good chance that the glow plugs are to blame. If you need to change your glow plugs yourself, here's a step-by-step guide.

How to change my glow plugs?

You can choose to replace just the defective glow plug, but we recommend replacing them all at the same time.

Step 1: Locate the glow plugs

The glow plugs are located on the left side of the engine, or the right side if you're facing the hood. Removing the plastic engine cover may improve access, or at least visibility.

Step 2: Remove the engine cover

Remove the plastic engine cover if your vehicle has one. Take it easy, as it's simply clipped on. To remove, remove the screws and lift the cover up.

Step 3: Remove the electrical connector

A long plastic rail covers it. It can be unclipped or unscrewed and disconnected. It's often held in place at both ends by metal brackets, which you'll also need to unscrew.

Step 4: Lug cover removal

Remove the black plastic caps from the spark plug electrical connection threads. These can be removed by unscrewing.

Step 5: Unscrew terminals

Unscrew the spark plug terminal nuts. Remove the spark plug terminal, being careful not to lose the washer under the nut. Remove the power strip.

Step 6: Spark plug removal

Unscrew the top of the spark plug using your wrench. Preferably use a magnetic socket wrench.

Step 7: Pre-clean the channels

Use a long-nose blower to blow compressed air into the spark plug shafts to remove any scale deposits.

Step 8: Clean the channels

Use a special reamer to clean the entire channel. Apply grease to the reamer to prevent scale debris from falling into the combustion chamber. Insert the reamer into the duct and continue cleaning. Blow into the duct again to remove any remaining grease and debris.

Step 9: Unpacking and handling spark plugs

Unpack new spark plugs with extreme care. A spark plug that has been weakened by impact could break in the engine during the next disassembly or even during operation, given the heat cycles.

Step 10: Thread coating

To facilitate the next disassembly, apply a high-temperature (copper) grease to the spark plug threads.

Step 11: Approach and tightening

Carefully insert the spark plugs into their sockets, then screw them into place. If the threads are clean, there should be no hard spots when tightened by hand.

Tighten the spark plugs with the torque wrench. It is recommended that this operation be performed when the engine is cold.

Step 12: Reconnect wires

Reassemble the electrical connections in reverse order of disassembly.

Step 13: Reassembly of removed components

If you had to remove a diesel fuel line or intake manifold to access the spark plugs, carefully reinstall them. Make sure all components are properly seated and secured.

Is changing glow plugs complicated?

Changing glow plugs on a diesel engine may seem complicated, but with the right tools and some basic knowledge, it's quite doable. However, it's important to note that this task requires precision and patience. Depending on the model of your car, access to the spark plugs may be restricted by other engine components. Also, be careful not to damage the threads when removing and reinstalling the spark plugs. Finally, checking the resistance of the spark plugs with an ohmmeter or multimeter is a critical step in determining whether or not they are defective.

How long does it take to replace glow plugs?

The time it takes to change glow plugs depends on the experience of the individual and the specifics of the vehicle. For a professional mechanic, changing glow plugs can take between 1 and 2 hours. For an amateur, it may take longer, up to 3 to 4 hours, depending on skills and tools. However, these times are estimates and may vary depending on various factors such as the accessibility of the spark plugs, the condition of the vehicle, and any complications encountered during the process.

That's it, you've changed your glow plugs. Now you're ready to start on the right foot with the right engine.