Glow Plug vs Spark Plug: What’s the Difference?
What’s the real difference in the glow plug vs spark plug debate? While they sound similar, these parts serve entirely different functions in diesel and gasoline engines. A spark plug creates a continuous spark to ignite fuel, while a glow plug is a heater that helps a diesel engine start in the cold. This guide breaks down their unique designs, operating conditions, and failure symptoms like hard starting or misfires. Understand their maintenance needs and why you can’t swap one for the other.