It’s a usual scenario: You’re out on the road when you suddenly hear a strange noise from under the hood. When this happens, there’s a good chance you are dealing with an engine knock.
This occurrence is not a good sign and may even lead to more serious engine trouble if unresolved. There are a number of remedies to reduce engine knock, such as using thicker engine oil.
But will thicker oil stop engine knocking completely? A quick answer for you is no, as it can only be a short-term solution. Read along and learn how this go-to solution may save your engine.
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Can Thicker Oil Stop Engine Knocking?
The key to knowing whether a thicker oil can stop engine knocking is understanding what an engine knock is and what triggers this alarming sound.
1. What is an engine knock
As the term suggests, an engine knock does sound like a knock or tap on the door, although a bit deeper. It occurs when there is an imbalance of air and fuel in one or more cylinders of your engine.
You usually hear an engine knock when the engine is running, and the sound can become more frequent and louder as the vehicle accelerates. There are times when you can also hear it, even when the engine is idle.
2. Causes of engine knocks
Other factors that may lead to an engine knock include bad-quality fuel, wrong spark plug timing, worn-out bearings, and clogged cylinders.
3. Thick oil as a solution
Using a thicker oil is commonly suggested to quiet engine knock as it provides a lubricating film to reduce the metal-to-metal contact within the engine which causes the unlikely noise.
While it helps lessen the sound, it should not be construed as an end-all engine knock treatment and may not be effective in all situations.
A thicker oil may only reduce the knocking sound in these cases:
- Lifter noise – Using thicker oil may stop lifter noise, but only if it is caused by worn-out lifters and not when lifters are out of adjustment.
- Rod knock – A rod knock means there is a problem with the internal moving parts of the engine. A thicker oil may extend the life of an engine with rod knock, but be reminded that this is just a temporary solution.
- Oil shearing – Shearing happens when the oil becomes thinner due to high pressure and temperature. As the oil loses its viscosity, the metal parts are not properly lubricated, thus making a knocking sound.
In some cases, using an oil additive for rod knock may help lessen the noise, but make sure you use the right additive because it might cause more harm to your engine.
When Thicker Oil is Not Enough
As mentioned earlier, thicker oil is merely a band-aid solution to an engine knock and does not address the root cause of the problem. There are instances when not even the thickest motor oil will put an end to your dilemma.
It is, therefore, helpful to identify the various underlying causes of an engine knock and have them fixed accordingly as soon as possible. Here are some of them:
1. Carbon deposit build-up
Over time, an engine accumulates carbon deposits that clog cylinders and fuel injectors, producing multiple detonations in each cylinder that come in the form of an engine knock.
To get rid of carbon build-up, you should use good quality fuel, clean air filters regularly, and check or replace spark plugs as recommended by the vehicle manufacturer.
2. Worn-out rod bearings
Commonly known as a rod knock, the noise is due to excessive space between a damaged connecting rod bearing and crankshaft.
Depending on the severity of the damage, the rod bearing and crankshaft may be repaired, or, in a worst-case scenario, the engine would have to be replaced completely.
3. Loose spark plug
A loose spark plug can cause misfires and uneven ignition of air-fuel mixture inside the combustion chamber, which, in turn, produces a knocking sound. This should not be taken lightly as it may lead to more serious problems, such as decreased fuel efficiency and engine damage if left unchecked.
Have your spark plugs checked regularly and replaced every 30,000 miles or according to your car manufacturer’s recommendation.
4. Fuel with a low octane level
A low-octane fuel requires more energy to light and affects fuel efficiency, which causes an engine knock.
On the other hand, high-octane fuel is more stable and resistant to high pressure and therefore more resistant to knocking.
Switch to a higher-octane fuel with carbon-cleaning additives to prevent further build-up in other parts of your engine.
5. Low engine oil
Running your engine with oil below average level may cause friction among the moving parts of the engine, thus producing a knocking noise.
It is best to regularly check your engine oil level. Engine knocking after a low-oil refill may help lessen the noise temporarily, but that doesn’t mean that your engine is free from internal damage due to lack of lubrication.
In addition to keeping adequate engine oil levels, manufacturers recommend changing the oil every 3,000 to 5,000 miles to maintain fuel efficiency and help keep your engine in top condition.
You should also remember that driving with an engine knock is highly discouraged. It’s a bad idea to continue driving with an engine knock as this may only worsen your engine’s condition and lead to more damage that is more difficult and expensive to repair.
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Hearing an engine knock should not be a cause for panic. However, it should not be taken lightly as it almost always means you are facing a more serious or even costly situation.
Will thicker oil stop engine knocking or not depends on the nature of the unwanted noise. It may work in some cases and may have an impact on the engine’s overall performance.
Knowing the signs and nature of an engine knock is one step in addressing the problem, but getting help from a qualified mechanic goes the extra mile in getting the job done.
Working with Vernon and Ryley has been a great experience for me. Together with the rest of the team, I hope to create reliable and useful information for our readers, no matter where they are and their experience with car maintenance.