Glow Plugs Replacement Service in Suprise & Goodyear, AZ

What are Glow Plugs and what do they do for my Diesel?

While most diesels have Glow Plugs, others use what is called a Grid Heater or Intake Heater, but there are some Diesels that use a combination of Glow Plugs and Grid Heaters. Glow Plugs are located inside the combustion chamber through the head, and they bring an intense heat to the inside of the combustion chamber. The tip of the Glow Plug gets red hot to heat up the cylinder temperature. The main job of your Glow Plugs is to assist with the initial startup or your Diesel when it is cold outside.

A Grid Heater or Intake Heater pre-heats the air before it is drawn into the combustion chamber. A Grid Heater is like the heating coils on your hair dryer, air blows through the coils and makes the air hot.

Unlike your typical gasoline motor, diesel engines run on compression to create combustion, and there is no spark to cause ignition. The compression ratio on a Diesel motor can vary but is always much higher than a gas motor because they use heat to create ignition. By compressing the air/fuel mixture in the cylinder, heat is created, which ultimately ignites the fuel when injected and then forcing the piston to cycle.

Glow Plugs, Grid Heaters and/or Intake Heaters are used in most modern diesel motors on a regular basis, even in Arizona! Depending on the outside temperature, Glow Plugs, Grid Heaters, or Intake Heaters can take longer to heat the cylinder air in colder temperatures. For example, if it is 20 degrees outside it will take your Glow Plugs, Grid Heater, or Intake Heater longer to heat up the cylinder temperature to the manufacturers ‘optimum temperature’ before your diesel will fire up.

Is there any maintenance required for a Glow Plug, Grid Heater, or Intake Heater?

Unfortunately, there is not really any maintenance you need to do in most cases. Most vehicle owner’s manuals will advise you when your Glow Plugs should be changed. At Champs Family Automotive, we recommend, at a minimum, replacing your Glow Plugs every 100k miles. On more modern Diesels (2004/2005 and newer) you can get a check engine light that may come on if you are having a problem with your Glow Plugs. On these more modern Diesels the onboard computer registers the amperage of each Glow Plug. If your Glow Plugs fall outside of their optimum operating amperage a check engine light may come on. Most older Diesels (2004 or older) will usually give you little to no warning signs that your Glow Plugs are failing, which is why it is always better to be proactive versus reactive. If you do not change your Glow Plugs before they fail, repairs can get very costly.

How many Glow Plugs does my Diesel have?

If your Diesel has Glow Plugs, you will have a Glow Plug for every cylinder. Some Diesels have Glow Plugs and a Grid Heater. Other Diesels do not have any Glow Plugs and only rely on a Grid Heater or Intake Heater. There are also Diesels that have more than one Grid Heater. If you are not sure if you have Glow Plugs, a Grid Heater, or an Intake Heater your local mechanics at Champs Family Automotive will be happy to help you determine what your Diesel uses.

What happens when my Glow Plugs fail?

If you do have a Glow Plug, Grid Heater or Intake Heater fail, you may notice a difference right away depending on the time of year. If the temperature outside is cooler, 50 degrees or lower, you may experience: misfires, abnormally rough start, or a check engine light may appear on your dash, longer cranking times etc…You may notice that your vehicle takes longer than normal to start. If the temperatures outside are relatively warmer, above 50 degrees, you may not experience any of the problems listed above until the temperature outside begins to cool down.

I have to replace my Glow Plugs, what brand should I use?

We recommend OEM (Original Equipment Manufacturer) Glow Plugs. Stay away from aftermarket or cheaper brand Glow Plugs whenever possible. Your Diesels ECM (Engine Control Module), PCM (Powertrain Control Module) or GPCM (Glow Plug Control Module) is programmed to identify the Glow Plugs resistance in your vehicle, so replacing them with aftermarket parts may cause an issue. OEM Glow Plugs are recognized by your onboard computer system and these Glow Plugs are manufactured to very specific specifications, which are proprietary to the manufacturer. Aftermarket Glow Plugs are typically set to a slightly different specification, this may cause your Glow Plug light or check engine light to go on prematurely. Aftermarket Glow Plugs may be cheaper, but remember, they are cheaper for a reason. If you must use aftermarket Glow Plugs, just be on the lookout for changes or issues when starting your motor.

Can I only replace 1 Glow Plug or should I replace all of them?

Remember, if you have Glow Plugs, you have 1 Glow Plug for every cylinder in your Diesel. All your Glow Plugs go through the same trauma, and all do the same amount of work. If one fails, the chance of having an issue with another one is high. We do understand that customers may not be able to afford to replace all the Glow Plugs at one time which is why we do our best to provide options for our customers. If you are unable to replace all the Glow Plugs in your diesel, we encourage you to do at least one bank (i.e., the driver side or passenger side) at a time. A ‘bank’ would be half of the Glow Plugs in your motor. We can replace only the one that failed, but the likelihood of the others failing shortly thereafter is high.

Best practices for my Diesel and Glow Plugs

  1. When you go to start your Diesel:
    • If you have a Glow Plug light on your dash (Note: this is on older generation vehicles), this light will usually light up when you turn your key in the ignition. Wait for this light to go out before you start your vehicle. This is an indication your Glow Plugs have heated the cylinder temperature properly for ignition.
    • Some Diesels have a ‘WAIT TO START’ light that may appear on your dash when you turn your key in the ignition. This light works the same as a Glow Plug light does. The light will turn off once the Glow Plugs, Grid Heater or Intake Heater have heated the cylinder temperature adequately for ignition to happen.
    • If your Diesel starts by push button you may not see either of the lights mentioned above. When you push the start button though you may have a 1 or 2 second delay which is the computer inside your Diesel activating your Glow Plugs, Grid Heater, or Intake Heater.
    • You should ALWAYS wait for your Glow Plugs to warm up before starting your diesel.
  2. Change your Glow Plugs at a minimum of every 100k miles or as specified by the manufacturer.
  3. Do your best to use OEM Glow Plugs.
  4. If you must replace your Glow Plugs, we encourage you to replace ALL the Glow Plugs at one time to minimize the risk of damage to your motor.

At Champs Family Automotive, we are always here to help educate, inform, and advise our customers on best practices and repairs for your Diesel and gas vehicles. If you ever have any questions or concerns our staff has the knowledge and expertise to help guide you through the necessary repairs to properly address your concerns.