How Many Air Filters Does a BMW 328i Have?

A BMW 328i typically has two main air filters: one engine air filter and one cabin (micro) air filter. Some model years and specific trim configurations may add a small auxiliary filter element or charcoal layer in the cabin filter assembly, but for maintenance and purchasing purposes, owners usually need to think in terms of these two primary filters.

Understanding the BMW 328i and Its Filtration System

The BMW 328i designation has been used across several generations of the 3 Series, including the E36, E46, E90/E91/E92/E93, F30/F31, and early G20-era equivalents in some markets. While engines and chassis have evolved—from naturally aspirated six-cylinder units to turbocharged four-cylinders—the basic filtration setup has remained consistent: a dedicated air filter for the engine and at least one for the passenger compartment.

The Engine Air Filter: What It Does and How Many There Are

Across standard BMW 328i models, there is one primary engine air filter. This filter cleans the outside air before it enters the intake system, protecting internal engine parts from dust, sand, pollen, and other contaminants that could cause wear or interfere with fuel-air mixing.

Engine Air Filter Configuration by Generation

The following list explains how the engine air filter is configured in different generations of the BMW 328i and clarifies whether any model uses more than one engine intake filter.

• E36 328i (1990s, inline-6): One rectangular engine air filter housed in a plastic airbox near the front of the engine bay.
• E46 328i (late 1990s–early 2000s, inline-6): One main engine air filter in a dedicated airbox; no separate secondary engine intake filter.
• E90/E91/E92/E93 328i (mid-2000s–early 2010s, inline-6): Still one engine air filter; some performance versions or aftermarket intakes may divide the filter element, but the OEM intake uses a single serviceable filter.
• F30/F31 328i (2012–2015, 2.0L turbo four-cylinder, N20 engine): One panel-style engine air filter in a top-mounted airbox. Despite the turbo, there is not a second standard “engine air filter”; the turbo shares the same intake filtration.
• Later 330i/328i-equivalent models (e.g., G20 330i in some markets rebadged or cross-referenced as a successor): Still one primary engine air filter; some have an integrated sound resonator or ducting, but not a second filter element for normal service.

Across these generations, BMW sticks to one primary engine air filter as standard. If an owner encounters a second intake filter, it is usually part of an aftermarket performance kit rather than original BMW equipment.

The Cabin Air Filter (Microfilter): The Second Major Filter

The second major filter in a BMW 328i is the cabin air filter, often called the microfilter. Its job is to clean the air that comes into the passenger compartment through the HVAC system, capturing dust, pollen, soot, and, in some versions, odors and certain gases via an activated charcoal layer.

Cabin Filter Layout and Variants

The cabin air filter arrangement does vary slightly between generations and regions, but for the driver, it is usually treated as one service item, even if the assembly uses two smaller elements inside one carrier.

• Older generations (E36, early E46): Typically a single, long cabin filter cartridge located under the cowl at the base of the windshield or behind the glove box, depending on market and right-/left-hand drive configuration.
• Later E46 and E90 generation: A main microfilter assembly that may be built from one or two filter panels inside a frame. BMW still specifies it as one cabin filter set for maintenance.
• F30/F31 328i (2012–2015): Usually a two-piece set (left and right) behind the glove box or under the dash. Though physically two panels, BMW and parts catalogs treat this as one cabin filter “kit” or “set,” replaced together.
• Charcoal vs. standard: Many 328i vehicles are equipped with a charcoal-activated microfilter option. This does not add an extra filter count; it just changes the material and performance of the existing cabin filter.

In practical terms, a BMW 328i has one cabin filter assembly, even if that assembly is made up of two panels. When buying parts, you’ll reference a single cabin filter (or filter set) for the vehicle.

Are There Any Other Filters to Consider?

While the question focuses on air filters, technicians and owners sometimes talk about several other filters that can cause confusion about the “number of filters” on the car. These are important, but they are not air filters in the traditional sense that the question implies.

Other Common Filters on the BMW 328i

The list below outlines additional filters on a typical BMW 328i and where they fit in the vehicle’s systems, to clarify what is and is not counted as an air filter.

• Oil filter: Cleans engine oil, not air. Located in an oil filter housing, usually on top of the engine on later models.
• Fuel filter: Filters fuel, not air. On some generations, it is integrated into the fuel pump module in the tank; on older models it is an external serviceable canister.
• Transmission filter: In automatic transmissions, a filter screens transmission fluid inside the pan or integrated with the pan. Again, this is a fluid filter, not an air filter.
• PCV or crankcase ventilation elements: Certain engines (for example, N20 in the F30 328i) use internal separators or small mesh elements as part of the Positive Crankcase Ventilation system. These are sometimes described as “breather” filters but are not listed or serviced as separate engine air filters.

These components are crucial for reliability and performance, but they serve different systems and should not be counted as air filters when answering how many air filters the car has.

Typical Owner Experience: What You Actually Replace

For a BMW 328i owner following a normal maintenance schedule, there are two air-related filter services you will commonly encounter: the engine air filter replacement and the cabin air filter replacement. Service intervals vary by market and driving conditions, but both items appear regularly on routine maintenance lists.

Service Patterns in Real-World Use

The following points outline how owners typically interact with these two filters over the life of the vehicle.

• Engine air filter: Often replaced every 20,000–30,000 miles (about 30,000–50,000 km) under normal conditions, sooner if driving in dusty or polluted environments.
• Cabin air filter: Frequently replaced every 15,000–20,000 miles (around 24,000–32,000 km) or once a year, particularly in urban areas with heavy pollution or in regions with high pollen levels.
• DIY vs. professional service: Both filters are relatively straightforward to replace with basic tools on most 328i models. Many owners handle them at home, while others include them in dealership or independent workshop service packages.
• OEM vs. aftermarket: Original BMW or OEM-equivalent brands (such as Mann, Mahle, or Bosch) are widely recommended. Upgraded cabin filters with activated carbon and HEPA media are increasingly popular for better interior air quality.

From the driver’s perspective, this translates into a simple maintenance reality: you buy and replace one engine air filter and one cabin filter set at their recommended intervals, keeping both the engine and the occupants breathing clean air.

Model-Year Nuances and Edge Cases

Because BMW 3 Series platforms and regional configurations can differ, some owners report minor variations that might sound like extra “air filters.” However, these seldom change the standard answer of two primary air filters.

Potential Sources of Confusion

The following examples highlight situations where owners may think their 328i has more than two air filters, and why the underlying count usually remains the same.

• Split cabin filter elements: On F30 328i models, the cabin filter is often sold and installed as a two-piece set. Even though two physical panels are present, they function as one cabin filter assembly.
• Performance or aftermarket intakes: Some owners install dual-cone or multi-filter performance intakes that use two small filters in place of the original airbox. These are not OEM and do not reflect the factory filter count.
• Charcoal/odor filters within HVAC: In some markets, additional odor-absorbing layers or enhanced microfilters can lead to confusion. These layers are integrated into the main cabin filter rather than separate filters.
• Marketing terms: Brochures sometimes describe “fresh air” and “recirculation air” filtration, but both are handled by the same cabin microfilter assembly, not multiple separate filters.

Even allowing for these nuances, service schedules, factory parts catalogs, and workshop documentation align on the basic layout: one engine air filter and one cabin filter assembly for a standard BMW 328i.

Summary

A BMW 328i, across its major generations, is equipped with two primary air filters in factory configuration: one engine air filter that protects the engine by cleaning intake air, and one cabin (micro) air filter assembly that cleans the air entering the passenger compartment. While the cabin filter can be split into two panels and aftermarket or performance setups can introduce additional elements, the OEM design and normal maintenance routines revolve around these two filters.

How much does it cost to replace the air filter in a BMW 328i?

between $102 and $160
The average cost for a BMW 328i Air Filter Replacement is between $102 and $160. Labor costs are estimated between $64 and $94 while parts are priced between $38 and $66. This range does not include taxes and fees, and does not factor in your unique location.

Do BMW’s have two engine air filters?

In a BMW, there are two main air filters: the cabin air filter and the engine air filter. When routinely changed, both can help prevent harmful particles from getting into a vehicle’s engine. The cabin air filter is behind the glove compartment under the dashboard, or under the hood of the vehicle.

How many air filters are in a BMW?

Your BMW has a cabin air filter and an engine air filter, and both should be routinely inspected and replaced as needed.

Where is the air filter in a BMW 328i?

So here’s our N20 engine bay. And our air filter is going to be below here so yeah a little pro tip for you guys always get yourself some rubber gloves. That are disposable.