Gasoline and diesel engines have more differences than the type of fuel they burn. For example, instead of using spark plugs for fuel combustion, diesel engines use compression to heat the engine's air intake.So when fuel is sprayed into the cylinders, fuel is instantly burned. To help the engine's pistons increase the air's temperature, the engine is equipped with a glow plug. This plug is a small metal device with a heating filament on its tip. Once the ignition switch is set in the 'On' position, a relay switches the glow plugs on.The glow plugs can generate a temperature as high as 1000 degrees Celsius in a few seconds; the high heat level quickly warms up the engine block and the cylinders. When the engine block reaches a set temperature, the plugs automatically switch off.As useful as these plugs are, though, their capacity to generate heat decreases over time. When the time comes that you need a replacement glow plug, trust only Carparts.
• Direct-fit replacement for a damaged plug
• Designed to generate the maximum amount of heat
• Keeps your car's exhaust emissions under control
Buying 101: Getting the Right Glow Plugs
Glow plugs on diesel engines help in maintaining the warm temperature inside engines to efficiently and cleanly burn fuel. These plugs wear out overtime and would need replacing. However, not all aftermarket plugs are the same and compatible with engine type and car usage. Here are some things you must check when picking a new set for your engine.
Size and length
Glow plugs come in many sizes. Make sure the plugs you pick are compatible with your engine's specifications. Check if the plugs fit your engine. Measure the length of the plug to see if it can be mounted on the cylinder head. Plugs too long are unsuitable because it would extend beyond the plug's compartment. On the other hand, short plugs wouldn't even heat the engine effectively. Also compare the length of the heating element. Plugs with longer tips tend to be warmer than plugs with short tips.
Speaking of warmer or cooler plugs, also consider under what type of weather you usually use your car. Glow plugs are supposed to aid engines by warming them up for ignition when it is still too cold. As a general rule, if you drive in an area where the weather is rainy, snowy, or just cold, the warmest plugs are the right ones for your engine for better morning heating. For sunny and warm weather where the engine is partly heated because of the environment, less warm plugs are the way to go.
Powerful racing engines can get extremely hot especially when pushed to the limit. On a smaller scale, tuned engines are also warmer than their stock counterparts. Because these engines are naturally at a high temperature, the glow plugs for these must be relatively less warm. Install plugs too hot and you might end damaging your engine because of overheating.
DIY Installation: Put the Glow Back to Glow Plugs
Glow plugs to diesel engines are like spark plugs to gasoline engines. These help out in the combustion of the diesel fuel by keeping a warm temperature in the engine. It is important to have the plugs in good condition for a smooth ride. Busted glow plugs, especially during cold weather, can lead to hard starts.
Difficulty level: Moderate
- Socket wrench set
- Ratchet set
- Glow plug reaming tool
- Replacement glow plugs
Step 1: Turn the ignition off and disconnect the battery.
Step 2: Locate the glow plugs. These are usually found on the driver side of the engine, under the fuel lines. Some car models however have plugs located near the engine's center. Use your socket wrench to remove the nuts on the glow plug electrical lines. Save these nuts aside for the replacement plugs. Clean the wires and ends.
Step 3: Remove the glow plugs from the cylinders with the ratchet set. Once removed, clean the holes with the glow plug reaming tool.
Step 4: Insert the new plug to the hole and tighten with the ratchet. Reconnect the electrical wire to it and secure the nut removed from step 2.
Step 5: Finish the job by connecting the battery. Try to start the car and test to see if there is still a hard start, or if the glow plug indicator light on the dash still turns on.
The whole process can take about 1 hour.
- It is advisable to work at one glow plug at a time so as not to confuse where the wires connect.
- The fuel lines can be removed, before reaching for the plugs. The only downside is that reconnecting them requires some pumping to remove the air from it.
- Make sure dirt does not enter the holes when the plugs are removed.