How to Tell When It’s Time to Change Your Glow Plugs

Glow plugs are essential in any diesel engine. They heat the air and fuel before it goes into the combustion chamber for efficient fuel combustion. The temperature outside will affect the temperature of your diesel fuel. If it is too cold, the fuel won’t get hot enough to combust, which means there’s no power coming from the engine.

Diesel fuel is denser on a molecular level than regular fuel. It may appear cloudy or gelled if it gets too cold. As the temperature drops, the molecules will start to bond, which gives it a hazy appearance. This can lead to clogging and poor engine performance.

That’s why glow plugs are so important. They heat up the fuel to prevent bonding and gelling in diesel fuel systems. While glow plugs are meant to last for the long haul, they likely won’t last forever. Here are some of the most common warning signs that your glow plugs need to be replaced:

Check Engine Light

This light goes on when something is wrong with your engine. It might hint at any number of potential problems, so it’s best to bring your vehicle to a licensed mechanic. If your glow plugs aren’t working correctly, they will likely activate the check engine light.

Hard Start

The engine needs the glow plugs to start burning fuel. If the plugs aren’t working properly, the engine may have a hard time starting in cold temperatures or it may not start at all. A hard start can also be caused by a bad battery or poor fuel. Once those issues have been addressed, check the glow plugs to see if they need to be replaced.

Engine Misfiring

So many things need to go right in order for the diesel engine to fire correctly. They use a high rate of compression along with the heat from the glow plugs to get the engine moving. If the compression rate is off, the fuel is bad, or the fuel mixture fails to reach the right temperature, the engine will likely misfire.

Rough Idling

As the glow plugs take on more damage, the engine will need more time to start as it warms the fuel to the proper temperature. This can result in rough or long idling. You may notice white smoke coming out of the exhaust until the engine starts.

Poor Fuel Efficiency

Temperature affects fuel efficiency. The fuel may be blended with additives in frigid temperatures to lower its freezing point. However, this fuel will have a lower energy content compared to regular diesel. The operating temperature of the engine will need to be adjusted to make sure all the fuel gets burned. The glow plugs can help provide additional heat to account for these differences.

If the glow plugs aren’t working properly, the engine’s performance will take a hit. Some fuel may not get burned in the combustion chamber. The engine will need to work overtime to make up for these losses.

White Smoke

If there’s white smoke coming out of the exhaust, it usually means the engine didn’t produce enough heat to burn all the fuel. Unburnt fuel will then escape out the exhaust. In cold weather, this may produce white smoke as well as a potent fuel odor.

If you notice white smoke when the engine is still starting up, your glow plugs might be to blame. However, if it continues after the engine has started, check your injectors for signs of wear and tear.

White smoke can also be a sign that something’s wrong with the vehicle’s cooling system. If the valve or cooler is damaged, shop for replacement ECR coolers and parts based on your make and model.

Black Smoke

Black smoke occurs when there’s too much fuel and not enough air in the combustion chamber. Faulty glow plugs can disrupt the air-fuel ratio. This can also be a sign that something is wrong with the combustion process.

Experts say new glow plugs should last up around 100,000 miles, so you shouldn’t run into these problems often. If your glow plugs are damaged, you can use a kit to replace them yourself. These are some of the easiest and most cost-effect auto parts to replace.

You can still drive with faulty glow plugs but the vehicle’s performance will start to suffer as a result. Be sure to address the problem as soon as possible to improve fuel efficiency and engine performance.

Don’t assume your glow plugs are to blame. If you notice these warning signs, it may be a sign that something else is wrong with your vehicle, such as the fuel injectors or the EGR cooler. Take the car to a licensed mechanic to make sure all your diesel truck parts are working at peak efficiency.

Glow plugs are designed to keep your fuel at the proper temperature in cold conditions. A slight change in performance can lead to problems on the road. Watch out for these warning signs to keep your glow plugs in working order.