Engine Knock On Startup Then Goes Away? 5 Prevention Ways

You have started up your car and heard a knocking sound from the engine. Sadly, you do not know why the engine knock on startup then goes away and how to stop this awkward noise. Don’t worry. This article is created for you.

We will show you some main factors leading to this problem and some methods to avoid knocking sound in the future.

How To Do If Your Car Makes Noise When Starting Then Goes Away?

Sometimes, you may hear a loud engine noise on startup, lasting for some seconds or a minute. This phenomenon is quite normal in almost all types of cars, and fortunately, you can stop this awkward situation with two basic steps.

Firstly, you have to heat the engine for a while. This method is really useful and effective.

The heating up process can ensure inside components such as the crank and oil are warm enough to perform normally.

The next action you have to take is to bring your vehicle to a professional mechanic store for a checkup. Various factors can be the causes of this buzzing sound after starting car.

Some of them are easy to detect, while there are some underlying issues that only professionals can diagnose and fix.

After identifying and fixing problems, you should do some maintenance process to avoid similar problems which may arise.

Why Does Engine Knock On Startup Then Goes Away? How To Fix It?

Below are five factors that make the engine rattle on startup then goes away. Although you are not a professional, you can easily detect these causes: piston slap, sticky valve lifter, worn engine, worn bearing wear, and oil-drain back.

Piston Slap

Before diving deep into the phenomenon of piston slap, you should understand what a piston is.

Basically, the piston is a thick metal disk that fits with the inside cylinder wall. It is connected to a rod that links them to the crankshaft.

Once the piston goes upward and downward, it forces the crankshaft to move along with it. The rotation created in this procedure will be transferred to your wheels throughout a driveshaft.

Engine piston

When you start or accelerate the engine, you may hear a “piston slap” engine noise. A piston moving up and down during rotation results in the knocking sound.

Especially in cold weather, the piston tends to move more.

The most common causes of piston slap are old pistons or worn-out spark plugs. However, once you heat the engine for a few minutes, there is little chance of this problem.

Sticky Valve Lifter

Another factor leading to a single knock when starting car is sticky valve lifters. Numerous factors create a sticky valve lifter. But, almost all of them are oil-related problems.

For example, the kind of oil you use, the type of oil filter, the condition of oil pumping, mileage, and even any components involving moving them.

If the engine oil doesn’t reach the inside parts correctly, it can cause a sticky lifter and poor engine seals and lead to piston slap or even dodge charger clicking noise when starting.

In this condition, the best solution is to change your engine oil at regular intervals and get your engine usually checked to avoid probable issues.

Worn Engine & Components

Common worn engine components that cause engine knocking noise during startup are water pumps, power steering pumps, exhaust manifold, and alternators.

These noises are considered normal working conditions, and your car will perform appropriately once a specific part fails.

<p>Bearings are in charge of keeping shafts and different rotating engine parts moving uninterrupted and smoothly.</p>

<p>Therefore, when these essential items are worn out, they will lead to noise in the engine, which explains why a <strong>car knocks when starting</strong>.</p>

<p>This problem also results in piston slap, entailing more serious problems.</p>

<p>The crankshaft’s core bearing renders the crank not to connect accurately with other engine parts. Luckily, the issue will disappear when the crankshaft is warmed up enough.</p>

<p>But this problem can reoccur once the inside temperature turns deeper and the crank shrinks.</p>

<h3 class=Oil-Drain Back

Usually, the oil filter has a check valve, which prevents your oil from going back to the system and draining from the filter.

If your oil filter has high quality, the valve is also good. So it can retain the oil in the engine block, ready for the next startup.

mechanic pouring oil into car engine
Oil For Car

However, if you use a cheap oil filter for your engine, the check valve does not seal properly.

In other words, each time you shut off your vehicle, the oil drains out of the block and accumulates in the oil pan.

Hence, whenever you start up your car, the drain sum must recirculate the oil completely.

Once this issue happens, you may hear some knocking sound and awkward noise of pumping oil to all components of your engine.

The noise will last only for several seconds when you start the engine. And then, it will stop when the oil is completely pumped and lubricate all the components.

Although the lubricant can protect the engine while your vehicle is working, the issues still happen when you start up your car.

How To Prevent Knocking Sound When Starting Car?

It’s never wise to wait until the problem occurs to fix it. We should take care of our vehicles well and not allow this issue to happen in the future.

In our article, we introduce five ways to avoid knocking sound when starting a car: consume high-quality oil, bring your car to an engine tune-up store, change the filter regularly, notice engine lights, and avoid driving on rough roads.

Invest In High-Quality Oil

Good quality engine oil can reduce engine wear and tear. Each time you start your car, it will get hot quickly. It means the engine parts broaden fast, causing friction among metal parts.

This can damage the engine if lubrication is not ensured properly.

The oil with high-quality assists in improving the engine performance by decreasing heat generation and lengthening the life of engine parts.

Moreover, it can clean up wear particles, remove carbon deposits from engine valves and pistons, and stop engine noise on startup.

Bring Your Car To An Engine Tune-Up Store

Taking your car to an appropriate engine tuning service helps avoid engine knock-on startup.

They ensure that the engine is performing smoothly without any obstacles such as carbon build-up or misfiring.

An Engine Tune-Up Store
An Engine Tune-Up Store

Regular checkups for your car can enhance the overall performance by making improvements, for example, adjusting the time of spark plugs, setting the air/fuel ratio, etc.

Change Filter Constantly

Dirty and old engine oil can cause sludge build-up, which impairs the engine performance.

Therefore, changing the oil filter regularly is a must to ascertain the engine oil remains pure and engine components are properly lubricated.

change car oil filter

Notice Engine Light

Another method to prevent a knocking sound when starting your car is noticing any warning signs of the engine light.

Whether it is a normal check engine light or sputtering, ignoring these symptoms can bring many problems or engine damage.

Check engine light

Avoid Driving Rough

You should limit the time driving aggressively if you want to prevent engine wear and tear. This type of driving involves speeding up or revving your car when you are in traffic jams.

As constant high speeds equal faster wear, one of the main factors causing piston slap on startup and damage to other engine components.


Does Loud Knock When Starting Car Disappear?

Yes. When the engine is warm enough, this knocking sound will stop. However, even after the noise has decreased, the engine has been harmed, more or less.

Due to this, it is important to ask the mechanic’s opinion if you hear any strange noise from your car.

How Much Money Does It Take To Repair Engine Knock?

Normally, when the problem is serious, repairing the engine knock costs from $100 to $500. If your engine needs to replace worn-out components, prepare to spend up to $1,000.

How Long Will Your Car Last With Rod Knocks?

Six months is the longest period that a rod knocking engine can endure before it blows up.

However, using an engine with a rod knock is not good because it can cause more damage and shorten its lifespan.


We have shared with you some reasons why the engine knock on startup then goes away.

We also suggest five solutions to prevent engine knock-on startup: use high-quality oil, take your vehicle to a mechanic store for a checkup regularly, change the oil filter constantly, check the engine light, and avoid driving rough.

Hopefully, our advice can help you improve your situation. Should you have other solutions, it would be great to share them with us.

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