Bosch offers one of the world's largest ranges of spare parts for vehicle repair. The focus thereby is on high quality and a long product life. This helps to keep people mobile all over the world. For more than 130 years, Bosch has pursued the goal of offering intelligent and reliable solutions to make life a little bit easier every day. Bosch Oil Filters: Bodyguard for the engine Bosch oil, fuel and air filters protect the engine and the injection system from particles and water. And cabin filters protect even the most valuable part of the car: they protect driver and occupants by filtering allergens, fine dust and harmful gases from the cabin air. Oil filter - design and operation Bypass valve: In case of viscous oil (e.g. in case of low temperatures), the bypass valve makes sure the engine is constantly supplied with oil by passing it by the filter for short instants. Non-return valve: Prevents the oil filter from running dry after turning off the engine and ensures engine lubrication right after starting the engine. A. Inflow of contaminated oil B. Filtration of oil C. Cleaned oil is conducted to the engine Urban traffic means stress for oil Short-distance trips and frequent cold starts can cause an excess of fuel within the combustion mixture and increased condensation. That is, ... the oil could be soiled by unburnt hydrocarbons and condensation causing premature aging of oil at high engine temperatures, these components can evaporate inside the oil circuit thus reducing the lubrication quality even further Therefore: Use high-quality engine oil combined with Bosch quality filters in order to prevent premature oil aging. When should I change my filter? Possible consequences of a silted-up filter: Loss of engine power. Increased oil consumption. Premature engine wear or even engine damage. Maintenance advice: Respect the interval of maintenance prescribed by the vehicle manufacturer and ask for Bosch quality.