3 signs of a bad glow plug (+Tips For a Longer Use)


It’s no longer news that Nitro RC vehicles provide a fun experience similar to a real car. These vehicles have become popular nowadays that the media has gone abuzz about them.

And as expected, they have some of the features of actual vehicles. For example, they use fuel and a glow plug just like regular cars.

How Do I Know If My Nitro RC Glow Plug Is Bad

The most noticeable sign of a bad Nitro RC glow plug is when the car will not start.
In that case, you can easily use a driver to test the glow plug and see if it glows when separated from the vehicle, or you can replace the glow plug with a new one right away.

If the vehicle starts and works well after the replacement, then you know the glow plug was bad, but if it doesn’t, then that probably wasn’t the issue.

There are 3 good signs of a bad glow plug:

Deformed Coils

Another sign of a bad glow plug are deformed coils. If they have a grey appearance instead of shiny silver, the coil will not glow as it ought to be. This is a sign that you need to change your glow plug quickly.

A glow plug could go bad quickly. Therefore, it’s better to buy the plugs in bulk and have some extras.

The Engine Dies as the Ignitor is Removed

Generally, the engine could be slow to start in warm weather and fail to start in cold weather.

Do you leave your ignitor on always? Then, your glow plug could become inefficient quickly. It could even make a new glow plug go bad within a few days.

Even if the car manages to start, a bad glow plug will make it hard to run correctly. This is due to low power and efficiency caused by improper combustion.

Secondly, you need to observe how the engine starts when you turn it on. If it dies as soon as you remove the igniter? Then, the glow plug needs a replacement.

The Plug Gets Hot but Doesn’t Glow

A functional Nitro RC plug radiates an orange glow, but you may need to adjust the drive to see it clearly on a cloudy day.

What happens if the plug gets hot but doesn’t glow? In that case, the plug is bad and needs a replacement. But, again, it is easier to notice if you use a proper glow testing device.

The plug needs to glow brightly. If not, the battery isn’t getting heated enough during starting.

Why Does Your RC Glow Plug Keep Burning Out

Do you constantly have to change glow plugs a few months after replacing them? The plugs might not be the cause; you should consider reaming the carbon.

Here are some of the causes of frequent glow burnout:

  • Overdue glow cycle
  • Excessive carbon buildup in the pre chambers
  • The incorrect spray pattern of the fuel injectors
  • The glow relay is not off

We got it covered: The Main 4 Reasons Your RC glow plug keeps burning out

Top Tips for Using Your Glow Plug Longer

Here are some tips to make your glow plug more efficient and last longer.

  • Ensure you remove the crud before the plug

Ensure the plug mounting hole is clean before you replace a plug. Also, the engine should be upside down during the replacement to prevent debris from entering.

  • Keep unused plugs in proper condition

Dirt and debris could easily attach themselves to your plug if loose and kept in an untidy place. Ensure you store them well and packaged inside a toolbox.

  • Don’t allow the engine to run until the tank is dry

When the engine burns fuel and hits the fuel line before running dry, it could decrease the useful life of your glow plug. 

  • Don’t over tighten the plug

The plug is tight enough once it snugs up against the head. Further tightening could warp the head, causing air leakage.

Now you know how to properly care for your Nitro RC car and when to change the glow plug. The suggestions in this guide could help you maximize the fun and reduce the inconvenience of a Nitro RC vehicle.

How Long Should a Nitro Glow Plug Last

Generally glow plugs will last you 3 to 4 gallons of fuel, but remember that a glow plug doesn’t have a set lifetime. Instead, the longevity of these plugs depends on how the engine is run between each glow plug replacement.

But not using your RC Nitro vehicle often is not an excuse why your glow plug shouldn’t go bad. If you use the vehicle a few times a year, the plug might still go bad.

Generally, most people change the RC glow plug after the vehicle’s engine has consumed 3-4 gallons of fuel.

Chances are, the glow plug might go bad at an inconvenient time. That is why it’s necessary to have an extra plug on hand in case you need to make a quick replacement.

If your RC Nitro car is floored, you should expect the glow plug to wear out faster than expected and consume more fuel.

Read the full article: How many gallons your RC glow plug can last

Can You Fix a Bad Glow Plug Or Should You Replace It?

Perhaps, you have wondered if it’s worth fixing your glow plugs. Occasionally, you may resolve to restore your glow plugs rather than replace them entirely. This is ideal when the plug was changed not too long ago, and you have observed (through testing) that it could be more efficient if fixed.

Consider replacing a glow plug if it announces a complete failure. If you continue to use a glow plug because the car engine manages to start each time could lead to more damage to the exhaust cleaning system.

So if you don’t want to take chances or you want to avert vehicle problems easily, it’s best to change a glow plug as soon as you notice that they are wearing out or becoming less effective.

Besides, glow blogs are relatively inexpensive, and you should consider purchasing a set rather than a single piece.

You Should Test Your RC Glow Plugs

There are different ways to test RC glow plugs. But most people prefer to use clamp meter.
You can test an RC glow plug without disconnecting anything using a clamp meter. This option is popular because it can test the entire system at once and are very easy to use.

This hassle-free testing method could help you check the plug’s heater element, power circuit, and heater connections.

Here is how to test the plug using the clamp meter:

  • Ensure the glow plug is turned off and the engine is cold
  • Switch on the clamp meter and choose “DC” mode.
  • Place the clamp close to the top of the glow or the plug wire
  • Ensure the clamp is safe from damage and completely closed
  • Turn on the plug
  • The consumption rates of glow plugs are 2A to 6A each. Then, turn off the plug

Repeat the process for each plug you want to test.

How Do RC Glow Plugs Work

The primary function of the glow plug is to provide proper ignition for the air or fuel mixture in a nitro or diesel engine. For an RC engine to work efficiently, it needs three things:

  • Ignition point
  • Fuel
  • Oxygen

The glow plugs work by heating the small coil of wire inside the plug, which is the element. A 1.5v battery inside the glow ignitor does this job.

As soon as the element heats up, the engine starts. The element doesn’t need any other power to remain hot or supply ignition to the engine.

Expand your knowledge – All You Need To Know About Nitro RC Cars