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August, 2019
How to Change Your Glow Plugs
Powered by the battery, glow plugs heat fuel in preparation for combustion. They regulate diesel engine temperatures for healthy vehicle performance.
While petrol cars use spark plugs to ignite fuel, glow plugs rely on compression rates to increase air temperature to combustion point in diesel vehicles.
Diesel engines require one glow plug per cylinder, meaning that they use up to ten plugs.
Glow plugs wear out with age, and cold weather causes them to deteriorate more quickly than they would in warm weather. Because of this, it’s important to regularly service your glow plugs and replace them when they are damaged.
Self-servicing your glow plugs allows you to save the time and costs required to have your car serviced at a garage.
The Tools You Need to Replace Your Glow Plugs
Regularly checking your glow plugs’ condition and replacing them when necessary will keep your engine in top condition. To change your glow plugs, you will need:
6 Steps to Replace Your Glow Plugs
Disclaimer: Every vehicle is different. This is a general guide.
Step One: Disconnect the Battery Cable
Open the bonnet and disconnect the black negative battery cable. Glow plugs use the full 12 volts from the battery, so this is a vital safety precaution. You may need a wrench to loosen the nut that connects the cable to the negative terminal.
For more info on where to find your glow plugs under the bonnet, click here.
Step Two: Remove the Valve Cover
If your glow plugs are protected by a valve cover, you will need to remove this. Unscrew the retaining screws around the outside edge of the cover, checking its condition in case this needs to be replaced too.
Step Two: Remove the Valve Cover
Disconnect the glow plug wires. You will find the glow plugs in the cylinder head, each connected to a wire that delivers the 12-volt power supply. The wires will be attached to the plugs with nuts, bolts, terminals or similar connection devices.
Note: pliers can be helpful when removing tight terminals.
Step Three: Remove the Glow Plug Wires
Disconnect the glow plug wires. You will find the glow plugs in the cylinder head, each connected to a wire that delivers the 12 volt power supply. The wires will be attached to the plugs with nuts, bolts, terminals or similar connection devices.
Note: pliers can be helpful when removing tight terminals.
Step Four: Remove the Glow Plugs
Remove the glow plugs using a socket and a ratchet. Place the ratchet over each plug, rotating it counter -clockwise. You may need to connect a deep well socket to the socket wrench to loosen the plugs.
Once you have removed each glow plug, you will be able to evaluate its condition. Glow plugs can break down once installed, so if you remove a broken plug, ensure you have recovered all the pieces from the engine.
Step Five: Insert the New Glow Plugs
Install the new glow plugs, positioning these by hand and using a wrench to secure them in a clockwise motion. Be careful not to over-tighten the plugs as this can cause them to break.
Step Six: Reconnect the Cables
Reconnect the glow plug wires, using a wrench to secure the nuts, bolts or terminals.
Reattach the valve cover – check your vehicle handbook in case your manufacturer requires the valve sockets to be torqued to a specific pressure.
Finally, connect the battery cable and turn your engine on to test your new glow plugs. You can also use a scan tool to test your plugs.
Quick Glow Plug Change Tips
- You should only ever remove (and fit) glow plugs using a manual torque wrench/socket.
- Service your glow plugs when the engine is cold to ensure safety.
- Change your glow plugs at the same time – if one is damaged, the others won’t be far behind.
Purchasing Your Glow Plugs
Enter your number plate into our car lookup tool to find out which glow plugs will fit your vehicle.
DIY Car Service Parts offers glow plugs at the lowest prices. We only supply car parts from trusted, reliable manufacturers. Search your registration plate to find the best glow plugs for you.
All DIY car service parts are manufactured by trusted, high-quality brands. Here are just a few of the brands that we stock.
About DIY Car Service Parts
Whether you’re changing your own car parts or saving costs by providing them to your local garage, DIY Car Service Parts is the ultimate site for easily identifying the vehicle parts that you need.
DIY Car Service Parts isn’t just about accessing car parts from the best brands at the lowest prices. With over 35 years’ experience in the automotive industry, we are experts in the car parts field. Our specialist team is on hand to answer any of your queries and offer valuable advice so that you can understand more about the ways that your car works and get savvy under the bonnet.
