Fuel tank ventilation system (Mercedes-Benz E-Class W210)

In order for the fuel from the tank to be consumed in the required quantity, air must enter it. Otherwise, a vacuum would be created in the tank, and the fuel supply would stop. In addition, the tank must be constantly cooled so that the fuel can expand when heated. When filling with fuel, a sufficient amount of air must leave the tank so that the fuel being poured in does not splash out of the filler neck. The air bleed tube is connected to the expansion tank, which binds and condenses the outgoing fuel vapors. When the fuel is heated, it expands, a certain volume of it gets into the expansion tank.

Warning! Handle fuel with care. Handling fuel requires special care. You should not take fuel system maintenance or repairs lightly. First of all, approach the issue of draining fuel from the tank thoughtfully. Protect yourself and others:

• - disconnect the ground wire from the negative terminal of the battery and securely insulate the battery terminals;
• - Do not drain fuel from the tank indoors. You will need a suitable device to drain it (for example, a hose with a squeeze bulb). Never drain fuel through the fuel level sensor hole or by sucking it out with your mouth through a hose - poisoning from highly toxic additives is possible;
• - keep a foam fire extinguisher within arm's reach and ready to go;
• - do not drain fuel from the tank into the inspection ditch - fuel vapors together with air can form an explosive mixture;
• - make sure that there are no electrical appliances, open sources of fire, heat or radio waves in the room;
• - pour fuel only into sealed containers. There are special fireproof containers with a valve cap for this purpose;
• - An empty fuel tank is a collector of fuel vapors. Be careful with it - there is a risk of explosion.

[Article was borrowed from the website: mercedesman.ru]