Your car is quite sophisticated mechanically, but it’s usually pretty easy to know when something is wrong. There are warning lights on your dashboard and then there are your own senses. Sights, smells and sounds all play important roles in alerting you to car problems. Engine knocking is just one of the signs there is a problem with the car engine. You may also notice a decrease in engine power and a loss of fuel economy. If you ignore the sound and keep driving your vehicle, in time, serious engine damage can occur. Find out what causes the knocking and what you can do to prevent it from happening by reading on.

What Causes Engine Knocking?

Think “controlled explosions.” Yes, every time you turn the key in the ignition and drive your vehicle, there are tiny controlled explosions going on under the hood. When your vehicle is operating efficiently, these explosions of the gasoline/air mixture are perfectly timed. When there is a problem in the engine that causes an incorrect balance of fuel to air or the mixture is ignited at the wrong time, the engine will make a knocking sound. If not corrected, engine damage will be the result. Here are some of the causes of engine knocking:

    1. Faulty Spark Plugs – It’s the job of the spark plugs to ignite the mixture of gasoline and air. Old and dirty spark plugs don’t function the way they were designed. They may deliver their spark at the wrong time which means the timing of the fuel/air explosion will be off. When that happens, the engine knocks. Over time, the cylinders and pistons can be damaged. Spark plugs should be replaced every 30,000 miles. When replacing them, it’s also a good idea to replace the spark plug wires. Click here to read more about the importance of regular tune-ups.
    2. Using Low Octane Fuel When Your Car Requires Premium – Many cars on the road will operate efficiently with lower octane fuel. Some, though, require the use of premium gasoline. If your car engine has a high compression ratio, you should be using a fuel with a higher octane (92 or 93). Using a lower octane gas in a car that has a high compression ratio will cause the premature ignition of the fuel/gas mixture and the engine will make that knocking sound. Consult with your owner’s manual to see what type of fuel you should be using in your vehicle.
    3. Buildup of Carbon Deposits – Today’s gasolines contain detergents that are designed to prevent carbon buildup in the engine. Unfortunately, some buildup still occurs. When this happens, there is less space in which the ignition of fuel and air can occur. Less compression space means the controlled explosions happen at the wrong time causing engine knocking. If this is the culprit of your engine knocking, you will need to have the cylinders checked and cleaned.

 The best way to prevent that knocking sound from happening is to have your car, truck or van serviced regularly. If you do experience engine knocking, the certified mechanics at Country Road Automotive can find and correct the problem. Click here to schedule an appointment in our auto repair shop for your next vehicle maintenance or tune-up now.

photo credit: Curtis Gregory Perry I-5 via photopin (license)