When you hear your door knocking, there’s probably someone or something waiting. The same thing happens when you hear your Toyota Premio engine knocking. An engine knock is perhaps the most feared sound by most car owners. However, it’s important to note that not all engine knocking sounds mean total, complete failure of your engine.
Combustion engines are designed to run smoothly and quietly from the moment you turn your key to shut down. Occasionally, your engine will produce a noise that is difficult to diagnose. A knocking noise from beneath your hood is the most typical engine noise, indicating an issue that needs fixing.
Fortunately for you, we have outlined the most common issues associated with engine knocking sounds.
Understanding Toyota Premio Engine Knocking Sounds
Understanding what causes the engine knocking sound in the first place is essential to understanding what could be causing it. It is vital to catch these issues immediately before you have to replace an entire engine or get inconvenienced for days to repair the problem.
- Low Octane Rating
Perhaps the most common cause of engine knocking sound is low octane. When fueling, make sure you don’t put fuel with an octane rating that is too low for your vehicle. It can create a knocking sound.
So, what is an octane rating? Well, it’s the fuel’s ability to resist premature detonation during the air-fuel mixing of the engine.
The combustion process causes the pinging and knocking beneath the hood. Your vehicle will also produce a knocking sound if you put adulterated fuel in it, which will affect its combustion process.
- Faulty Spark Plugs or Wrong Spark Plug Gap
Your engine’s spark plugs are what offer the electric spark that ignites the cylinder’s air-fuel mixture. Ideally, your car’s spark plugs are what is getting the engine up and running. Like any other component in your vehicle, the spark plugs are prone to wear and tear over extensive use.
Most vehicle manufacturers recommend replacing spark plugs after 45,000- 50,000 km. However, it is essential to note that spark plug longevity depends on the plug’s condition and type. If your spark plugs are old, they could be the reason behind your Toyota Premio engine knocking sound.
- Toyota Premio Bad Knock Sensor
Fortunately, engine knocking isn’t a frequent issue in modern cars. This is because the computer controls the vehicle’s air/fuel ratio, timing, and injectors. Modern vehicles even have a knock sensor developed to detect engine knocking, relaying the information automatically to the ECU (Engine Control Unit) for correction.
This means that a faulty knock sensor will allow the engine to continue knocking. Therefore, if you have a modern car and produce a knocking sound, check the knock sensor first. It’s an essential part of the diagnostic process.
- Carbon Deposits Interrupting Efficient Fuel Burn
Vehicle fuels are required to have some level or percentage of carbon cleaning detergent. But sometimes, they may not prevent the carbon deposits from forming. As your engine’s fuel begins mixing with oxygen, it burns.
Because diesel and gasoline contain multiple carbon molecules, carbon residue will spark plugs, valves, and other components in the combustion process. This reduces the average volume inside the cylinder, increasing the amount of compression, which creates a knocking sound.
While using a special additive or fuel Injector cleaner designed to clean carbon deposits will efficiently resolve the issue, it will be more beneficial to get the opinion of a professional mechanic.
- Bad Belt Tensioners and Pulleys
At times, the source of your engine knocking sounds isn’t probably coming from your engine at all. The source could be coming from the accessory belt. When the engine is turning, it turns a belt that is usually connected to several engine bay pulleys. This belt must be under the exact amount of tension so that it can rotate smoothly and quietly.
If the belt is stretched out for any reason, the tensioner doesn’t work correctly, or one of the pulleys gets bent or out of shape, your engine will produce a tapping, rattling, and slapping noise that can sometimes be confused for a knocking sound. Fortunately, fixing a noisy accessory can be as easy as replacing the belt, tensioner, or accessory pulley or making adjustments.
Engine knocking sounds could also mean catastrophic engine failure. If the knocking gets louder when you accelerate, there’s a check engine light, and you occasionally experience low power, you must have your Toyota Premio checked by a professional automotive service immediately.
— Motindechu (@motindechu) May 28, 2024 
