A glow plug is a small and useful component inside an engine that works when the ignition is on. The glow plug heats up the engine’s internal pistons and fuel injectors. Even if the engine is not started at that time. The tip of the glow plug gets extremely hot and glows red when the ignition is on, allowing the engine to start smoothly and quickly even in cold weather.
But sometimes the glow plugs in the engine go bad or the glow plug timer module is bad. This post will go into detail about the symptoms and replacement cost of bad glow plugs.
What Is Glow Plugs?
Glow plugs in diesel engines are components that are primarily used in diesel engines to aid in the ignition process. Glow plugs in diesel engines heat up during startup to increase the temperature of the air in the combustion chamber, ensuring efficient ignition of diesel fuel. Especially in cold weather, glow plug preheating helps with easy starting of the engine.
Symptoms Of Bad Glow Plugs
Symptoms of bad glow plugs may include an engine starting problem, a warning light on, white smoke issues, rough idling, engine misfiring, decreased fuel efficiency, or a poor accelerator.
Let us understand in detail the symptoms of bad glow plugs in any diesel internal engine.
1. Engine Starting Problem
You must have seen it often. That sometimes when the engine of your vehicle is in cold condition, then the engine starts having trouble starting. But once the engine starts, it starts smoothly and quickly after warming up. If the engine’s glow plugs are bad, then this type of engine starting problem can occur.
Because when the engine is in cold condition. And glow plugs are unable to heat the engine’s internal combustion chamber. Then the fuel mixture in the internal combustion chamber of the engine is not ignited due to cooling.
Hence the engine starts having problems. But once the engine reaches warm-up temperature after starting, the internal combustion chamber of the engine becomes hot. Due to which the fuel mixture starts burning easily.
Due to this, the engine starts easily and quickly when it is warmed up. Cold engine starting problems can also be a main symptom of a bad glow plug. However, this symptom can also be caused by other engine problems. You will need to inspect the glow plugs for this.
2. Glow Plug Warning Light
Sensors and switches are attached to the engine and other parts of the vehicle. Due to a fault in any of these parts, the warning light in the cluster meter may be continuously on or the warning light may start blinging.
Similarly, the most common symptom of a faulty engine glow plug is the continuous illumination of the glow plug-related warning light in the vehicle’s cluster meter or the glow plug warning light starts blinging. The most common symptom of a bad glow plug is a glow plug warning light coming on in the cluster meter.
3. White Smoke From Exhaust Issue
Diesel engines can often be seen with white smoke coming out of the exhaust pipe for the first 1–2 minutes after starting cold, often due to a bad glow plug. And this white smoke gives off the smell of half-burnt fuel. Because on starting the engine in cold condition, the fuel mixture does not burn in the right amount due to cooling.
Due to this, the unburned fuel mixture comes out of the exhaust pipe in the form of white smoke. However, temporary white smoke on cold starts can also be caused by other engine problems. such as – deterioration of engine head valve seals or slight wear of piston rings, failure of fuel injectors, etc.
If you see the symptoms of white smoke, you must get the vehicle inspected by a professional vehicle mechanic. so that the problem of white smoke from the engine can be detected and diagnosed.
4. Engine Rough Idling
A bad glow plug can cause a diesel engine to briefly run in a rough idle position during initial starting because it is difficult to ignite the fuel mixture in the internal combustion chamber of a cold engine. Due to this, the RPM at the idle position of the engine may be less than the normal rate.
And a decrease in engine performance can be seen. Engine starting at rough idle can be a symptom of a bad glow plug. However, there can be many other reasons for engine idling.
5. Engine Misfire
Bad glow plugs are often a symptom of diesel engine misfires. because the internal combustion chamber and fuel injectors are cold during the initial starting of the engine, due to which the fuel burning process in the internal combustion chamber of the engine does not get started properly. Due to which the engine starts misfiring for some time in the initial starting.
6. Poor Acceleration
Bad glow plugs are often the cause of acceleration problems on cold diesel engines on startup because the internal combustion chamber of the engine does not heat up due to a bad glow plug.
And the fuel mixture does not burn in the right quantity, due to which the performance of the engine decreases and due to this problem acceleration problem can be seen at the beginning of engine star
Glow Plugs Replacement Cost
The cost of a glow plug used in a typical engine can range from $20 to $60, and the labor cost of a professional auto mechanic can range from $50 to $100.
Generally, the replacement cost of glow plugs depends on the model of the vehicle and the brand and design of the glow plug.
Glow Plug 1Piece Cost – $20 To $60
4 Glow Plugs Cost = $80 To $240
Mechanic Labor – $50 To $100
However, mechanic labor to replace a glow plug can be expected to be higher or lower depending on labor time and experience. Engine glow plug replacement cost depends on the design and mechanics of your vehicle’s engine and on labor time.
If you have the proper tools and experience to replace the plugs. Then you can save the labor of a mechanic to replace the glow plug. making the cost of glow plug replacements affordable to you.
FAQ’s
Q. How do I know my glow plugs are bad?
If an engine’s glow plugs fail, you will first notice several symptoms of bad glow plugs, such as an engine starting problem, a warning light on, white smoke issues, rough idling, engine misfiring, decreased fuel efficiency, or a poor accelerator. Especially on cold days, a bad glow plug can cause a little trouble starting and a misfire.
Q. Is it OK to drive with a bad glow plug?
No, it is generally not recommended to drive with bad glow plugs. Because bad plugs improper combustion chamber temperature causes inadequate fuel ignition. However, glow plugs play an important role only when starting a cold engine. Once your vehicle’s engine reaches running temperature, it is not particularly needed.
