Mercedes Fuel Hose Install

Mercedes Fuel Hose Install

Every couple of years its always a good idea to replace the rubber components of your fuel system. I have this as one of my maintenance items to perform when I schedule a coolant change, every two years. If you are running bio diesel, you also want to change out the hoses, and then again every 2 years. No hose will last forever, this included Viton hoses that are touted as "bio hoses". These hoses are good but very expensive. Running bio diesel with your factory hoses is fine, just start with a new set and change every two years. Most bio/hose problems occur when someone starts to run straight bio and they have their old hoses. It will just speed up a leak and the hoses get blamed. So start with a fresh set before bio and you will be fine.

Please remember to recycle all your used fluids at an appropriate recycling center. Be mindful to not spill or splash fluids on yourself, others or the ground. Also as a safety tip please remember anytime you are working on, around or under your car, to wear safety glasses and secure the car with wheel stops and approved jack stands!

The first place to start is the supply hose. This hose feeds the inline filter and has a short section that goes from the filter outlet to the pump inlet. Just remove the clamps and install the new hose.

Next is the return hose also called the "cigar" hose. Yes it is funny shaped kind of like a cigar. There is a reason for this shape. The added diameter dampens the fuel return pulses as the fuel is hot coming back from the injection pump etc. This is the best explanation I have heard to date. But yes this hose also gets replaced.

The next set of hoses that get replaced are the injector return lines. These lines serve to reroute unused fuel that was not used by the injector and send it back to the filter and then on to the tank. This is the most overlooked hose and will leak if over a few years old. Lots of heat radiating from the engine shorten these hoses lives. Just pull each one off, and push the new hoses on. Don't forget the end cap on the last injector.

Now we must work under the car at the fuel tank. Please get a good set of ramps to do this, don't use a jack!

Chock the front wheel. You do have a chock don't you? A stout piece of wood will work in a pinch.

This hose is the fitted fuel hose and is the supply hose for the car. When you disconnect this hose it is best if the tank is near empty. When you remove this hose the contents of the tank will come out, so get a good bucket that is more than the amount of fuel in your tank.

This is the other end of the fitted hose. Just remove the clamp and pull the hose free from the line. I recommend cleaning the junction before you pull it off to keep dirt out of the fuel system.

The last 2 hoses coming from the tank are the return line and a vent hose. Just remove the clamps and pull them off. Install is just the reverse of removal.