Why your car gives low mileage after a service (and how spare parts affect it)

Why your car gives low mileage after a service (and how spare parts affect it)

Introduction

Many car owners notice that their vehicle gives lower mileage right after a service. It feels confusing because a freshly serviced car should perform better, not worse. This issue is often linked to the spare parts fitted during the process and how well they match your car’s specifications. In this blog, you will learn how specific components influence fuel efficiency and how to make the right choices, whether you prefer OEM or high-quality aftermarket parts.

How spare parts influence mileage after servicing

Every spare part plays a key role in maintaining your car’s efficiency. If a component does not match the manufacturer’s recommended specifications or is not installed correctly, it can affect how your engine consumes fuel. Below are some of the most common causes of a sudden mileage drop after service and how to fix them.

Air filters and restricted airflow

Air filters ensure that clean air reaches your engine for proper combustion. When the airflow is restricted, the engine compensates by burning more fuel, reducing mileage.

Cause: Wrong size or low-quality material

Sometimes, a filter with incorrect dimensions or substandard material is installed, which restricts airflow and leads to incomplete combustion.

Fix: Use filters recommended for your car model

Check your car manual to confirm the right air filter specification. Replacing the filter with one that matches your vehicle’s design ensures optimal airflow and balanced fuel use.

Spark plugs and combustion efficiency

Spark plugs are vital for igniting the air-fuel mixture inside the engine. When they fail to perform correctly, the fuel may not burn completely, which lowers fuel efficiency.

Cause: Mismatched heat range or worn electrodes

Using spark plugs with the wrong specifications or worn electrodes can cause incomplete combustion, poor acceleration, and a noticeable drop in mileage.

Fix: Install compatible spark plugs

Choose spark plugs that match the manufacturer’s recommendations. Always confirm the part number and heat range before replacement to maintain consistent engine performance.

Engine oil and viscosity

The viscosity and grade of your engine oil have a major effect on mileage. Oil that is too thick creates resistance, while oil that is too thin fails to lubricate properly.

Cause: Non-recommended oil grade

Using an oil grade that differs from what your manufacturer suggests can cause the engine to work harder, leading to higher fuel consumption.

Fix: Follow the manufacturer’s oil grade

Always check the owner’s manual or the manufacturer’s official website for the correct oil grade. Choosing the right type of engine oil reduces friction and improves fuel economy.

Tyre pressure and rolling resistance

Tyres play a bigger role in mileage than most people realize. Incorrect tyre pressure increases rolling resistance, which forces the engine to consume more fuel.

Cause: Pressure not reset after alignment or rotation

During servicing, tyre pressure adjustments are sometimes overlooked after wheel alignment or rotation, leading to uneven air pressure levels.

Fix: Check and maintain the correct tyre pressure

Inspect tyre pressure regularly using a gauge or at a nearby fuel station. Maintaining the recommended level improves mileage and ensures safer handling.

Final thoughts

A drop in mileage after a service can be frustrating, but it is often linked to small oversights such as incorrect spare parts or poor maintenance habits. Always verify which parts were replaced, confirm compatibility with your car model, and ensure correct installation.

Whether you use OEM spares for precise compatibility or aftermarket parts for better affordability, focusing on quality is the key to maintaining efficiency. If you want an easy way to find verified options, Autozilla offers both OEM and aftermarket parts that fit perfectly with your vehicle’s requirements.

Explore genuine and reliable car parts online with Autozilla and keep your vehicle running efficiently.