Sometimes after you get an oil change, your car might start to shake or vibrate when it is stopped or in park.
Experiencing your car shaking at idle following an oil change can be concerning. This unexpected issue may stem from several potential causes.
Identifying and addressing the root cause promptly is important to ensure the smooth operation and performance of your car.
Here’s why car shaking when idle after oil change happens:
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1. Use of oil with the wrong viscosity
Using the wrong oil viscosity means using a motor oil that doesn’t match the recommended viscosity or thickness specified by the car manufacturer.
Viscosity is the oil’s resistance to flow, and it’s denoted by a numerical value, such as 5W-30 or 10W-40. The first number (e.g., 5W) indicates the oil’s viscosity at low temperatures, while the second number (e.g., 30 or 40) represents viscosity at higher temperatures.
When the wrong viscosity oil is used, it leads to several issues that cause your car to shake when idle due to poor lubrication, oil pump strain and causes difficulty in starting your car in cold weather.
Oil viscosity directly affects how well it flows and lubricates engine components. If the viscosity is too high (thicker than recommended), it might struggle to flow properly, leading to inadequate lubrication.
This can cause increased friction between engine parts, resulting in rough idling and vibrations.
Thicker oil also puts excessive strain on the oil pump, which may struggle to circulate it efficiently throughout the engine. This can lead to improper lubrication and contribute to engine vibrations.
Using oil with the wrong viscosity for cold temperatures can make it harder for the engine to start, causing rough idling until the oil warms up and flows more easily.
The solution:
If the wrong oil viscosity has been used during the oil change, have it drained and replaced with the correct oil as soon as possible to prevent potential damage to the engine.
To prevent these issues, always refer to your car’s owner’s manual to determine the recommended oil viscosity and type for your specific car model.
Using the correct oil ensures proper engine lubrication, performance, and longevity, reducing the likelihood of experiencing vibrations or other engine-related problems after an oil change.
2. Improper oil level
An improper oil level in the engine—either overfilling or underfilling—can contribute to car shaking when idle after an oil change.
Overfilling causes increased pressure and aerated oil while underfilling causes insufficient lubrication in the engine.
Too much oil in the engine can lead to excessive pressure within the lubrication system. This excess pressure can cause the oil to foam, reducing its effectiveness as a lubricant.
The foamy oil might not adequately coat engine components, leading to increased friction and vibrations.
Also overfilled oil might get aerated or whipped up by moving engine parts, causing air bubbles to form within the oil.
This aerated oil loses its lubricating properties, impacting engine performance and potentially causing shaking or vibrations.
When there’s not enough oil in the engine due to underfilling, critical engine parts might not receive adequate lubrication. This can result in increased friction between metal surfaces, leading to rough idling and vibrations.
Solution:
Have the oil level checked to identify if an incorrect oil level after an oil change is the underlying cause of the shaking and for it to be corrected as soon as possible to prevent potential damage to the engine.
To avoid these issues, it’s important to follow the manufacturer’s recommended oil capacity specified in the owner’s manual when performing an oil change.
Checking the oil level using the dipstick after an oil change also helps to ensure it falls within the appropriate range.
Related: Why is my car shaking when parked and driving? (Here’s why)
3. Dirty or clogged fuel injectors
A car shaking when idle after an oil change can also be due to dirty or clogged fuel injectors which affects the air-fuel mixture and combustion within the engine.
When fuel injectors become dirty or clogged, they may not spray fuel evenly or in the right pattern into the engine cylinders.
This irregular fuel distribution can cause inconsistent combustion, leading to engine misfires and vibrations at idle.
Clogged fuel injectors may disrupt the precise balance between air and fuel needed for efficient combustion. This imbalance can result in a rich or lean air-fuel mixture, causing rough idling and engine shaking.
The solution:
Cleaning or servicing fuel injectors helps restore their proper functioning. Fuel injector cleaning additives or professional cleaning services are available to remove deposits and buildup.
Severe clogs or damage require the replacement of the fuel injectors.
Have a qualified mechanic inspect the fuel injectors to determine if cleaning or replacement is necessary.
4. Faulty spark plugs or ignition system
Faulty spark plugs or an issue within the ignition system can directly impact the combustion process, leading to car shaking when idle after an oil change.
Worn or faulty spark plugs may not ignite the air-fuel mixture effectively. This incomplete combustion can cause engine misfires, resulting in uneven running and vibrations, especially at idle.
A malfunctioning ignition system, including components like ignition coils or spark plug wires, can also lead to erratic ignition timing. This timing irregularity can cause the engine to run unevenly and shake at idle.
The solution:
Have a qualified mechanic conduct a thorough inspection. They can assess the condition of the spark plugs, ignition coils, wires, and other related components to determine if replacements or repairs are needed.
5. Vacuum leaks
Vacuum leaks occur when there’s an unintended gap or hole in the vacuum system, allowing unmetered air to enter the engine. Such leaks can lead to a car shaking when idle after an oil change.
Vacuum leaks disrupt the balance between air and fuel needed for proper combustion. The additional, unmeasured air entering the engine can cause a lean air-fuel mixture, leading to rough idling and engine shaking.
Vacuum leaks also cause the engine to run erratically, especially at idle, due to the irregular air supply affecting combustion and engine stability.
The Solution:
To diagnose and fix vacuum leaks, a mechanic should perform a diagnostic test to locate leaks in the vacuum lines, intake manifold, or other related components.
Once identified, repairing or replacing the affected parts can restore the proper air-fuel mixture and resolve engine shaking issues.
Related: Car not running right after oil change (Here’s why)
6. Engine mounts or transmission issues
Issues with engine mounts or the transmission can result in a car shaking when idle after an oil change due to their role in maintaining stability and reducing vibrations in the car.
Engine mounts secure the engine to the car’s frame, reducing vibrations and noise transmitted from the engine to the cabin.
Worn or damaged engine mounts can allow excessive engine movement, leading to increased vibrations felt throughout the car, especially at idle.
A malfunctioning transmission or related components can cause irregularities in power delivery and affect the engine’s operation, leading to shaking or vibrations.
The solution:
A qualified mechanic should the engine mounts and the transmission. They can assess the condition of the mounts, transmission, and related parts to determine if repairs or replacements are necessary to restore smooth operation and reduce vibrations in the car.