How To Stop Engine Rod Knocking On The Car?

You’re driving your pride and joy, and one day you can hear a strange noise originate from the car’s engine. It’s a deep rapping noise in there with a ball-peen hammer. Could it be the dreaded rod knock? and if yes how to stop engine rod knocking?

Rod knock is a tapping that comes from within your engine that typically increases with speed or when the engine is under load. Of course, several things can make a rod knock like noise. But if you really have rod knock, you need to know what you’re dealing with.

In case the knocking noise seems to go away once the engine warms up, then it’s most likely not rod knock, so check your exhaust gaskets and other possible sources.

What Is An Engine Knock?

Knocking occurs when fuel burns unevenly in your engine’s cylinders. When cylinders have the correct balance of air and fuel, fuel will burn in small, regulated pockets instead of all at once. After each pocket burns, it creates a little shock, igniting the next pocket and continuing the cycle. Engine knocking happens when fuel burns unevenly and those shocks go off at the wrong time. The results become an annoying noise and potential damage to your engine’s cylinder walls and pistons.

What Are The Things That Can Cause A Rod Knock?

The most common cause of rod knock is a spun bearing, which is when the rod bearing essentially jams up. This causes the gap inside to expand so that every time it goes around, the excess play creates a knocking sound.

1. Spark Plugs Faulty

Your engine’s spark plugs deliver the electric spark that ignites the cylinder’s fuel or air mixture. Spark plugs are essential to getting your engine up and running. Like other parts in your car, spark plugs age and break down over time. Most auto manufacturers recommend having new spark plugs installed about every 30,000 miles. But spark plug longevity depends on the condition and type of spark plug.

If you’re not using a manufacturer-recommended spark plug, or your spark plugs have seen better days, this could be what’s causing that distracting knock.

Left unreplaced, faulty spark plugs could lead to a drop in engine power and a loss of fuel economy. This is the first step you can notice to know how to stop engine rod knocking.

2. Low Octane Fuel

Gasoline comes with different octane ratings, which is why you have so many options when you pull up to the pump. The higher a fuel’s octane rating, the more compression it can withstand before igniting. If your engine was engineered to handle high-octane fuel, using the regular kind could lead to excess engine noise.

High-octane fuel does tend to be more expensive than regular fuel. While saving a few bucks at the pump may seem like a great reason to go with regular, engine knocking means it may be time to spend a little more. Long-term use of the wrong fuel could damage your engine and decrease your fuel economy.

When you’re getting fewer miles per gallon and potentially paying for engine repairs down the line cheaper gasoline won’t be saving you any money at all.

3. Carbon Deposits

All fuel sold is required to include carbon cleaning detergents to help prevent carbon deposits from clogging up your cylinders. Unfortunately, some deposits still form. There is less room for the fuel and air to reside when they do, leading to increased compression. As you learned with fuel, changes in fuel compression can lead to nasty knocking sounds.

Excess carbon buildup can lead to problems in the combustion process and damage your engine’s cylinders. The resulting decrease in performance can also lead to lower gas mileage or overheating. This is the way you have to notice and know-how to stop engine rod knocking

How To Stop Engine Rod Knocking?

Might as well replace the crank main bearings while you are there and try to figure out in case some factor you can address, such as a faulty oil pump, might have caused the rod bearing to fail.

1. Replacement Of Sparks Plug

Fortunately, spark plug replacement is a pretty budget-friendly fix. In addition to replacing of spark plug replace air and fuel filter replacement and a fuel system cleaning. Regular tune-ups can bring power and efficiency back to your car and potentially put an end to engine knocking. If you are not sure when your spark plugs were last replaced, schedule an appointment at your local auto care. The technicians can help you determine which tune-up service is right for you.

2. Fuel Type

First, check your owner’s manual. What’s your recommended fuel type and are you using it? In case you need, step up your octane level at your next fill-up or use an octane booster to increase performance. If this doesn’t seem to help after a few fill-ups, your problem might stem from something else.

3. Clean The Cylinder

Have your cylinders cleaned by a professional? An engine manufacturer, recommends that you check your cylinder for carbon build-up every 100 hours of operation, just to be safe. If you are short on time and expertise, feel free to bring your car to your local auto care for an inspection and tune-up. Technicians can help your engine get back in shape.

Can You Drive A Car With Rod Knock?

Well, it’s not going to fix itself. And it’s true, once rod knock starts, it isn’t going away on its own. It’s an eventual death sentence for your engine, and how long your engine runs will depend on a host of factors. Sometimes you can cheat death for a while by moving to a thicker oil or using an additive, but you are only prolonging the eventual tears since, at some point, the problem will worsen until the engine finally seizes up.

The sooner you fix it, the less damage will be done, mainly to the crank.

How Much Are Engine Rod Repair Costs?

The cost to repair an engine rod knock depends on several factors, including How long it’s been knocking, The extent of the damage, If it’s a high-performance engine or not, and If the engine is salvageable or not

The last thing you want is to find out your engine need to be rebuilt, which can cost between 2,500$-4,000$. Or worse, a total engine replacement, which can reach as high as 10,000$ or more.


The longer you wait, the worse things will be.

Regardless, it’s a costly repair, no matter how you slice it. However, rather than waiting, tackling it early can quickly become the difference between whether a repair is possible or if you need a new engine.

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