Engine Rattle On Startup Then Goes Away

Engine Rattle On Startup Then Goes Away; Why?

When you have a car and try to start it and rev it, instead of the usual noises you hear rattling noises of the engine, you got a significant problem in the car. 

So if you notice the unsettling and disturbing sound coming out of your vehicle every time you start it, you should take it to a mechanic shop to get it fixed. 

The rattling sound of the engine is a sign that you have something wrong in your car that needs immediate attention.

There could be several reasons why your car’s engine rattles on starting and then goes away, like you could have a poor quality of gasoline, low engine oil, faulty starter, slapping pistons, and many more. 

What’s that rattling sound coming from your engine? Sometimes it happens after you start the vehicle. So until you take your car to a good mechanic for proper diagnosis, you won’t know what went wrong and the root cause of the problem. 

It lasts for a few seconds and then goes away. The vehicle may not have any other symptoms, but it can also have rough idle or reduced power. 

Your car’s engine is cooling system may need to be flushed to remove corrosion and scale through the system. A clogged radiator or cooling system can cause coolant to back up and get into the oil.

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Why Does My Engine Rattle At Startup?

Engine Rattle On Startup Then Goes Away

The answer is that some engines have a small metal motor called an impeller attached to the crankshaft. The impeller pushes air over the engine, creating air resistance to push the car forward. When cold, this resistance creates a rattle noise. 

It is a common question that people ask about their car. Your car rattles when it starts because of the air resistance created by an air pump on the engine. 

And after a few seconds of running, the engine doesn’t rattle anymore. Because there is a little motor attached to the crankshaft, it’s called an impeller, and it moves air over the engine so that it will start.

So there could be many problems inside your car that cause the rattling noise, and one of them is because of the impeller. 

This allows an engine to run in cold weather conditions where air resistance creates a rattle noise. Your car doesn’t rattle anymore after a few seconds of running. Once the vehicle has enough speed to overcome more resistance than the impeller creates, air resistance no longer causes any noise.

5 Reasons Why A Car Engine Knocks On Startup Then Goes Away.


A car engine is supposed to knock on startup then go away, but sometimes it ends up staying like this. This can be due to various troubles, such as a water leak. Here are five reasons why your engine might knock before going away:

Sticky Lifters

 If the lifters don’t move when the pistons slide past them, they tend to stick in place and make more noise than usual as the piston moves back in forth between its retracted position and fully extended position. 

Damaged pistons, rings, and other components may also cause your engine to knock on startup before going away.

Piston Slapped

Piston slapped occurs when the piston hits the cylinder head in an attempt to go back and forth. This problem is easily fixed if you work with a less expensive engine that doesn’t cost as much if a famous brand makes it. 

A popular, more expensive engine brand will cost you more due to the higher-quality materials used. Still, they are also harder to work with because accessing all parts can be more complex than working with an ordinary car engine. 

Oil Drain-Back

If the oil drain-back is broken, it can cause the engine to knock on startup and go away. This condition can be caused by a few problems: a worn camshaft lobe. 

If this part is used for too long without being replaced, it should be fixed immediately.

Worn Components

Some of the engine components designed to last for thousands of miles tend to wear out after some time. 

If you don’t replace these components in time or try to renew them yourself, you might experience problems like piston slapped or sticky lifters that make your car engine knock on startup before going away forever. 

Worn-out Drive Belt

A worn drive belt can also cause your engine to knock on startup then go away. Over time, the tension from this part of the car engine wears out, and it will no longer be able to move in synchronization with other parts inside the engine. 

This is another reason why you need to take your car in for a service routinely so that they can check out other parts of the engine while they check out this one.

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What Are The Causes Of Rattling Noises In Your Car’s Engine.

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A little-known fact is that car rattles are one of the most common car issues. Vibrations in the engine can come from many different sources, all requiring other solutions, but it can be difficult to pinpoint exactly what’s causing the problem. 

Below are some of the common causes you can face with your car. 

  • Timing Belt: 

A broken timing belt will often cause an unpleasant metallic rattle when accelerating or decelerating; if this happens, consult your vehicle manual for instructions on replacing it. 

  • Misaligned Valve Train: 

If you’re hearing a rattling when you shift your vehicle into gear, then your valve timing may be out of alignment. The best solution to this problem is to have your mechanic adjust it.

  • Bad Water Pump: 

If your car starts making a rattling sound when you turn on the water, there may be a problem with the cooling system. Replacement is usually simple: consult your owner’s manual for fixing it.

  • Loose Exhaust System: 

You might hear a loud rattling sound coming from under the hood or underneath the vehicle; if this happens, you should check the exhaust system for loose hangers or clamps that need tightening.

  •  Poor Quality Gasoline: 

If your vehicle is making a rattling sound, then it may be time to upgrade to a different grade of gas.

  • Broken Fan Clutch: 

If you’re hearing rumblings coming from the engine compartment, you should check the fan clutch; the parts will need replacing if it’s broken. A bad gas cap may also cause rattling in your engine.

  • Faulty Starter: 

A bad starter will cause your vehicle to make a loud rattling sound when starting; pull over and have your starter checked for problems if this happens to you. If a bad starter is an issue, diagnose it appropriately to solve this issue. 

So if you notice any loud noises or rattling sound coming inside of your car, then look for these causes to find the exact problem. It would be best if you did not waste any minute taking your vehicle to the mechanic shop to get it repaired. 

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