What is the function of a glow plug in a diesel engine?

A glow plug is a heating element that heats incoming fuel and air to encourage efficient fuel combustion in a diesel engine. The fuel combustion starts your engine so that you can drive.

Can you start a diesel without glow plugs?

Yes, a diesel engine will run without glow plugs. In fact, many diesel engines DO NOT EVEN HAVE glow plugs, and they run. Glow plugs are not an integral part of the diesel engine operating cycle: rather, they are merely a starting aid that some engines are equipped with.

What are diesel glow plugs made of?

Ceramic-type glow plugs (Figure 9.1) for diesel engines have a ceramic heater element inside the heating section. The properties of silicon nitride make it an excellent material for these glow plugs. Silicon nitride has superior resistance to heat, corrosion, and thermal shock.

What causes glow plug failure?

Usually, glow plug failure is due to excessive heat, or high voltages reaching the plug. High voltage can be caused by a controller that is starting to go bad. Additionally, if there is faulty wiring, or a problem with the controller, the glow plug(s) may be receiving power all the time.

At what temperature do glow plugs work?

The combustion chamber heat comes from compression pressure and glow plug heat. It needs to reach at least 450° F / 232° C for ignition to take place. If the glow plugs are faulty, the engine chamber will not reach the required temperatures.

Do you have to warm up a diesel engine before driving?

The only warm up time you really need is about 30 seconds, just to get the oil circulating. In fact, diesels won’t reach operating temperature unless they’re under load, so warming an engine up prior to driving is actually just prolonging the process.

How bad is it to cold start a diesel?

Diesel engines are harder to start in cold weather because they depend on high temperatures created by compression to ignite the injected fuel. In fact, it is five times harder to start a diesel engine at 0°F (-17°C) than it is to start one at 80°F (26°C).

What voltage do diesel glow plugs use?

Most glow plugs require 12V, though some use other voltages. Make sure the engine is cold, and the glow plugs are turned off. Disconnect the power cable from the glow plugs. If you don’t do this, your tester will be powering all the glow plugs instead of just one.

Are glow plugs easy to replace?

With continuous use and extreme temperature variances, glow plugs are a hard working part. Rough starts or misfires while starting, smoking when starting, and trouble starting in cold conditions are all basic signs of a failing glow plug. They tend to be relatively cheap and are easy to replace with the right tools.