i have been useing biodiesel for many years in an E300D with no fuel related problems at all.. untill they [government] changed the fuel to USLD.

the biodiesel swells orings and the new low sulfur, low aromatic fuel hardens and shrinks and cracks the old orings. once they are replaced you should have no problems. they will absorb the new fuel and not be shocked from rapid changes.

At this age the w210s need new lines and rings anyway. 10 years is enough for a small piece of rubber. change to viton will last forever; will not absorb any chemical, new or old.

this week i'm running b100 soy. next week b99 cotton seed.

Thank you to all of my friends (in archive) on this forum that saved me time and many dollars on my 1st fuel related problem.