99 e300 fuel line question
 

Hello,

Could someone advise me of which fuel line is the supply and which is the return on a 1999 E300. The lines are located on the diver side near the brake master cylinder. There are two are plastic lines one is larger than the other.

They are rubber lines not plastic and the top one is the supply line, bottom one the return line. If you follow the top one it goes to the fuel filter housing. I recently changed mine and I am changing the return one tomorrow.


EDIT: That may not be correct, the dealer told me this info. I remember seeing a diagram with the fuel flow for the 606 on a thread awhile back, I will search for it.

http://www.peachparts.com/shopforum/diesel-discussion/274778-my-97-300d-will-not-start-no-fuel.html

This thread had the fuel flow diagram. I was incorrect. The Bottom line near the firewall is the fuel supply line.

Fuel lines
 

I am referring to the two plastic lines that come from the fuel tank and terminate on the driver side firewall near the mater cylinder. There they are connected to rubber fuel lines for connection to the engine. One is larger than the other. Which one is the supply and which one is the return?

Answer:

The bottom one

The larger 10mm hose is the supply and the smaller 8mm hose is the return.

If you follow the lines you will know your answer, that is why I put the flow diagram up. The bottom goes to the pre-glow heater and then to #1 in the chart.