How to Test Kubota Glow Plugs

Being skilled in tractor maintenance is essential for the longevity and efficiency of your Kubota vehicle. While knowing how to test Kubota glow plugs might be a lesser-known aspect of tractor upkeep, it's key to your tractor's optimal performance.

In this guide, we’ll walk you through multiple testing methods, including using a digital multimeter, plug tester, and clamp meter, ensuring you have the necessary knowledge to choose a suitable approach. However, if this proves to be too difficult of a task, you can always leave it to the professionals and contact an authorized Kubota service.

How to Test Kubota Glow Plugs in 3 Simple Ways

When learning how to test tractor glow plugs, it's worth remembering that there is more than one way to go about this practice. Depending on what you have at your disposal, you may inspect the glow plugs of your Kubota vehicle using a digital multimeter, a plug tester, or a clamp meter. However, if this proves to be too difficult of a task, you can always leave it to the professionals and contact an authorized Kubota service.

Using a multimeter 

Before you begin testing glow plugs with a multimeter, first, you must check the multimeter specifications. Inspect the resistance range to see if the multimeter can detect lower-scale ohms of 1Ω to 6Ω. If dealing with a multimeter that cannot measure low resistance, you can check only the "continuity" function. 

To eliminate all confusion, we'd like to add that in digital multimeter testing, we examine two aspects - electrical resistance and power supply. 

How to test glow plug resistance 

1. Before you begin the assessment procedure, a few things require your attention. First, ensure that the Kubota engine is cold. Then, unplug the power cable from the glow plug. If you forget to disconnect the cable, you will measure the resistance of all the glow plugs together. 
2. Once done, you can move on to the multimeter setup. This process is straightforward as you only need to turn on the device and select 'Ω' mode. 
3. Next, move on to connecting the multimeter leads. One should be connected to the ground on the engine while the other terminal goes on top of the glow plug. 
4. When properly placed, the multimeter will display the resistance of the glow plug. The glow plug is in good condition if the results show a resistance lower than 6Ω.
5. Once finished, turn off the glow plugs and disconnect the lead from the plug. Repeat the same procedure with all the remaining glow plugs on the engine. 

How to test glow plug power supply 

1. Prior to measuring the voltage of the glow plugs of your engine, it's crucial to look up the voltage assigned by the manufacturer. Most Kubota glow plugs generally have a 12V, but some might feature a different voltage, which is why it's worth looking into. 
2. As with the previous procedure, inspecting the power supply also requires the engine to be cold. 
3. To begin this process, turn on the multimeter and select the 'DC voltage' mode. The multimeter leads are placed accordingly, as in the previous procedure, with one being on the engine and the other on top of the glow plug. 
4. Repeat the procedure for each of the glow plugs involved. 

Using a plug tester 

Using a plug tester is arguably the most complicated testing procedure. Thus, we recommend being extra cautious and having all the information at hand before you begin this process. Visit the manufacturer's website to check the voltage of the tester and ensure it's suitable for the battery you'll be using as a power supply. 

We should also note that tester and plug compatibility might also be an issue. We recommend doing research and ensuring you are following manufacturer instructions. 

1. This glow plug test begins by connecting the tester's ground supply lead to the engine's power supply ground. 
2. Then, connect the plug tester's supply lead with the power supply output. 
3. Next, connect the tester's plug ground with the glow plug ground. The easiest way to find the glow plug ground is to look for a threaded portion on the glow's body. 
4. Finally, connect the tester's plug power lead with the glow's power terminal. 
5. Once everything is set in place, you can enable the plug tester's output, revealing the results on its display. Depending on the type of plug tester you are using, you can expect the display to show either a current or a certain range. 
6. Once done, disconnect the tester's power lead and ground and place them on the next glow plug. 

Clamp meter 

Those interested in testing glow plugs without removing or disconnecting anything, then using a clamp meter is the way to go. The clamp meter is a more sought-after option because it allows several parameters to be tested simultaneously. 

We can assess resistance, electrical connections, and the power circuit using this device. 

1. As with the previous procedures, the primary precaution is to ensure the engine is cold and the glow plugs are turned off. 
2. After ensuring everything is set, turn on the clamp meter and select the DC current mode. The diagnostic process depends on properly positioning the clamp meter. There are two ways that the clamp meter may be fit. It can either go around the glow plug power wire or on top of it. 
3. After ensuring the clamp closes fully, turn on the glow plugs. The clamp meter display will show the electrical current of the glow plug. For Kubota vehicles, it is typical for the measurements to range between 2A to 6A. 
4. Once done, repeat the process with the remaining glow plugs. 

How Long Do Tractor Glow Plugs Last

Typically, glow plugs are said to last around 100,000 miles, which means that you are not very likely to experience glow plug problems very often. Still, this doesn't mean that your glow plugs will not fail before that. With years of experience in Kubota maintenance, we can say that glow plugs regularly get overlooked. 

Many owners fail to understand the significance of glow plugs and often miss out on the signs of failing glow plugs. While the issues they cause are not as easily noticeable in water climates, when temperatures fall below zero, the engine is not likely to start if you have worn-out glow plugs. 

Some of the most common signs of faulty glow plugs include the following: 

• Difficult engine ignition (or no ignition) in cold weather
• Decreased power
• Lower engine efficiency 
• Engine misfire
• Increased vehicle smoke emission 

Conclusion 

As we explained, testing Kubota glow plugs can be conducted in several ways depending on the tools available. Each method has its merits and whether you will be using a digital multimeter, a plug tester, or a clamp meter depends on individual skills and circumstances. 

What all three procedures have in common is that it’s essential to follow the correct instructions and precautions, ensuring a cold engine and proper connection. Understanding how to test Kubota glow plugs not only prolongs their life but also prevents common problems such as difficult ignition and decreased power.