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Do Cummins Have Glow Plugs? (Read This First!)

The technology used in the creation of motors and engines are constantly evolving and being modified. A car engine from the 80s will have significant differences to the ones that are being created in this day and age. Some parts are changed and some are omitted altogether.

Do Cummins have glow plugs?

Cummins engines and motors do not come with glow plugs anymore. Instead of glow plugs, a single heater grid works as their only source of heat aid. Experts at Cummins believe the heater grid is a more reliable and effective way of heating all the heat that enters into the air intake.

Glow plugs are mainly found in diesel engines and their function is to heat up the air that is present in the combustion chamber. The glow plugs all work simultaneously to help the air to climb up to the required temperature.

However, this same mechanism is not adapted by Cummins motors. Both the 6.7L and 5.9L Cummins engines opt for a single heater grid instead of multiple glow plugs to heat the air that comes to the heat intake.

This single heater grid works efficiently enough that there isn’t a need for glow plugs. This is why Cummins motors do not come equipped with glow plugs.

Does any Cummins have glow plugs?

None of the Cummins engines that are manufactured nowadays come with glow plugs. The engine’s lack of glow plugs isn’t noticeable because of the presence of heater grids which warms the combustion chamber air during any cold operation.

Therefore, it is not necessary for Cummins engines to come with glow plugs as the single heater grid essentially is able to perform the same functions.

6.7 Cummins:

6.7 Cummins does not come with glow plugs. Instead, it comes equipped with the standard single heater grid that is common among most Cummin engines.

There are diesel engines and ford power strokes that come with glow plugs but 6.7 Cummins does not share this feature with them.

Dodge Cummins:

Similar to the 6.7 Cummins engine, Dodge Cummins also does not have glow plugs and instead uses a heater grid.

That helps heat up the air that enters the combustion chamber. Due to the presence of the heater grid, the Dodge Cummins does not need to have multiple glow plugs added to it.

Cummins ISX:

Cummins ISX also does not have glow plugs as they are not necessary in the Cummins ISX engines.

They are not needed to help run the engine because the Cummins ISX engines have a single heater grid that works the same as glow plugs, if not better than them.

12 valve Cummins:

Engineers who work on 12 valve Cummins have mentioned that since there is a single heater grid in the intake manifold of the 12 valve Cummins engines, it can run smoothly without any glow plugs.

Thus, the glow plugs are not added to the 12 valve Cummins engines.

First-gen Cummins:

The first-gen Cummins also lacks glow plugs in the system because the part of the engine where the traditional glow plugs system is supposed to be, there is a single heater grid which works to heat the air that comes into the air combustion chamber. Therefore, there is no need for a glow plugs system.

Why do Cummins not have glow plugs?

Unlike many other engines, Cummins engines and motors do not come with glow plugs. This might make many people curious as to how Cummins operates in cold operations if the glow plugs are absent.

Well, to ensure the engine’s function runs smoothly even during cold operations, Cummins has a single heater grid which acts as the heated air system for the entire Cummins engine.

The heater grid is able to heat up the combustion chamber air, operate and turn on and off on it’s own, similar to the glow plug mechanism. Cummins engines opt for compression instead of glow plugs as they believe it to be a more reliable method for their engines.

What is the glow plug in a diesel engine for?

Glow plugs are a necessity for diesel engines because they need fuel, air and heat to run smoothly. Or to put it more simply, they need an ignition source and this is where spark plugs and glow plugs come in.

They are the ignition source for any combustion engine. While gasoline engines need spark plugs, diesel engines work better off with glow plugs.

The glow plugs are used to help the diesel engines with cold starts. Because during cold operations the hot surface will heat the charge that is surrounding it.

This is done by speeding up the evaporation process of the liquid diesel fuel that is present which then accommodates the ignition of the fuel-air mixture. This usually helps when the engine needs to start working in conditions with low ambient temperature.

What does Cummins have instead of glow plugs?

As we have already discussed, Cummins engines do not come with glow plugs. Instead, they employ a heater grid in the intake manifold of the system to help with cold operations.

The experts and engineers at Cummins have mentioned that after many tests and trials, they came to the conclusion that glow plugs were not necessary for their engines.

They claim that the single heater grid system is a much more reliable and better option to assist their engines during cold operations.

So, even though diesel engines work more efficiently, Cummins engines do not use them and will instead continue to use the heater grid system for the foreseeable future to help their engines to run seamlessly.

How long should you let a Cummins warm-up?

If you want your Cummins engine to run smoothly, then it is best to let it warm up properly before using it, especially when the temperature is close to or below zero.

Plus this does not take more than 3 to 5 minutes which is a good thing as almost everyone is in a hurry during the early hours of the day.

But the time needed to warm up may differ depending on which Cummins engine you are using. Therefore, we will look at both 6.7 and 5.9 Cummins engines.

5.9 Cummins:

5.9 Cummins should be allowed to reach a temperature of 190 or 200 degrees fahrenheit before running.

So, it is best to let it heat up for approximately 2 minutes. During this time, be mindful to keep the rpm below 1500 until the temperature reaches about 170 degrees fahrenheit.

6.7 Cummins:

6.7 Cummins takes a little longer than 5.9 Cummins before it can operate smoothly. However, it does work at a much lower temperature.

So, it is best to wait for about 5 minutes before driving and it is also wise to drive slowly for the first few miles and then pick up speed gradually for the best performance.

Can a diesel start without glow plugs?

Diesel engines can start without glow plugs. But they are an important part of diesel engines as they produce the required heat to help the engine start, run and also function properly.

The glow plugs are more necessary when the weather is colder and also since the cylinder compression is stronger in diesel engines which means they need more heat.

However, despite this diesel engine can start without the assistance of glow plugs. Because of this the newer designs have begun to exclude glow plugs.

A prime example is the military grade diesels which run just fine without glow plugs and the many newer diesel engines can run even if the glow plugs stop working.

Can you cold start a diesel?

It is possible to start a diesel engine in the cold but it will be significantly harder. As diesel engines sort of rely on the heat produced by compression to help ignite the fuel that is injected at the time of ignition. This makes it so difficult to cold start the diesel.

To avoid this, it is always best to allow the diesel engine enough time to warm up properly which will allow it to start and run without any hindrance.

Final Thoughts

Cummins engines don’t need glow plugs as the heater grid located in the intake manifold works to replace the benefits the glow plugs provide by heating up the air in the combustion chamber. Therefore, the glow plugs are excluded from Cummins engines and replaced with a single heater grid.