The STIHL air filter system: longer life and better performance

Why your tool needs an air filter

When an engine is running it continuously needs air for the combustion process. This air passes through a filter before it reaches the engine to guarantee that the combustion process runs as smoothly as possible, and to keep wear and tear to a minimum. This process filters out unwanted particles such as concrete dust, wood splinters and other fine debris from the surrounding air and to prevent them from entering the engine, where they could easily cause damage. Many STIHL chainsaws and all STIHL cut-off machines include an innovative long-life air filter system to further reduce this risk.

STIHL air filter in chainsaws: extended service life

Most STIHL chainsaws have an innovative long-life air filter system with routing to take the strain off the downstream filter elements. It works like this: 

• To begin with, the intake air is set in motion by the fly wheel; this flushes out the larger and heavier particles in the air. This pre-filtered air is conveyed along the routing channel to the air filter in your STIHL power tool engine.
• The air is then passed through the high-capacity air filter, so the air delivered to the engine via the carburettor or STIHL injection system is clean. In many of our power tools the air filter is interchangeable, meaning the filter material can be adapted to suit the conditions - polyamide filters for cold weather, for example, or our high-performance, innovative HD2 air filter made from polyethylene filter material. The HD2 air filter pores are up to 70% smaller than those in fleece and polyamide filters, meaning it can effectively filter even the finest dust from the air. The HD2 air filter is also oil and water-repellent, as well as being equipped with a highly effective seal that prevents unfiltered air from getting into the engine, thereby prolonging its service life. What’s more, HD2 air filters can be cleaned and reused multiple times: just remove the filter and spray with STIHL Varioclean, leave for a few minutes to allow the detergent to take effect, then rinse and dry before reinstalling. 

STIHL professional tip: For some chainsaw models you can upgrade your standard fleece air filter to the HD2 air filter. It comes in three variants to fit different chainsaw models

Stihl air filter system in cut-off machines: cyclone-strength power

STIHL cut-off machines all have a long-life air filter system that includes cyclone routing, a paper filter, and a fine dust filter. The innovative cyclone routing system means reduced need for daily filter cleaning and a much longer filter service life. This is how the air filter system works in detail: 

• In the first phase, the cyclone routing extracts around 80% of the dust particles in the intake air. Unlike conventional systems, these particles do not collect in the air filter, but are expelled back into the environment together with the cooling air. 
• Next, the paper filter removes particles from the air that has passed through the cyclone routing system. This efficient routing helps extend the service life.
• After the paper filter, the fine dust filter traps all of the remaining fine dust particles. 

Benefits of the STIHL air filter system

Long-life air filter systems offer a whole host of advantages. 

• Effective filtering: particles are removed from the air stream before reaching the air filter
• Longer filter service life: service intervals for cleaning and replacing the air filter are significantly extended. These intervals can vary depending on the filter material and frequency of use 
• Low-maintenance and user-friendly: STIHL long-life air filter systems do not require any specialised or complicated care
• Easy maintenance: cleaning the air filter on a chainsaw is straightforward. Details of the process can be found in the operating manual supplied with the machine

Summary: STIHL air filter system 

• An air filter removes unwanted particles from the air taken in by the engine
• STIHL develops a range of innovative air filters designed for the machine and application at hand. If you need a new filter, your nearest  STIHL Approved dealer will be happy to advise
• STIHL air filters guarantee a long service life for the machine, prevent premature wear of pistons and cylinders, and keep the fuel/air mix free of dust and debris