Bosch Oil Filters FAQ

Below are some frequently asked questions that Bosch have answered on oil filters:

1. How important is the country of origin, and how does it affect the filter quality?

The country of origin of Bosch filters does not matter at all since Bosch filters always feature quality "made by Bosch". The same ISO standards and Bosch guidelines concerning filter development and production are applied worldwide.

2. What does “opening pressure of the bypass valve” mean?

In case of low ambient temperatures or very soiled oil, the bypass valve makes sure the engine is constantly supplied with oil by passing it by the filter for short instants. Such viscous oil requires an increased pressure to be pushed through the filter. Once the pressure level reaches a predefined limit (= opening pressure), the bypass valve is opened. The accurate design of these bypass valves is an important quality feature.

3. Why are there both filter exchange boxes and filter inserts?

Shape and specifications of oil filters are set by the vehicle manufacturers. Basically, filter exchange boxes and filter inserts have the same function. In addition, filter exchange boxes are equipped with a bypass valve and a non-return valve. In the case of filter inserts, this job is performed by a firmly integrated filter housing.

In recent years, there has been a clear trend towards filter inserts among vehicle manufacturers as they do not require any metal housing and they are viewed as more environmentally friendly.