leaking return lines 96 MB E300

AFter running about 2500 miles on B100 my return lines are leaking at each injector on my MB 96 E300. Based on previous posts I presumed all lines on this vehicle were compatible with B10; the leaks may be due to age of lines, however, as I believe they are still original and hard after 130,000 miles. Anyone know what position MB is taking re: replacment with OEM silver/gray covered rubber lines or must I locate synthetic Viton? Any sources in D.C. metro area? Thanks.

Try www.mcmaster.com It shouldn't be expensive for the less than 2 feet that you'll need. On VWs many have found that the inter-injector return fuel lines get brittle after many miles, possibly due to heat.

Order #5119K41, thats 1/8ID - 1/4OD. You will find that 2 feet will be enough for you but order 4 so you can share or have spare. I never seem to have enough to go around.

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Originally posted by torkydzl
AFter running about 2500 miles on B100 my return lines are leaking at each injector on my MB 96 E300. Based on previous posts I presumed all lines on this vehicle were compatible with B10; the leaks may be due to age of lines, however, as I believe they are still original and hard after 130,000 miles. Anyone know what position MB is taking re: replacment with OEM silver/gray covered rubber lines or must I locate synthetic Viton? Any sources in D.C. metro area? Thanks.

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I believe that Mercedes uses hydrogenated nitrile rubber (such as Therban) lines, just like VW. Hydrogenated nitriles such as that are compatible with B100, but they do gradually harden and crack due to heat (unrelated to biodiesel). The inter-injector fuel lines get exposed to far more heat than any of the other fuel lines, leading them to gradually harden and crack. Using some biodiesel may or may not speed that up - but, those lines (assuming they are a similar material to what VW uses) can fail even if biodiesel is never used, due to the material not handling heat well. Viton is a much better choice for those particular lines, since handles heat far far better. As mentioned by others, try McMaster Carr. Search for viton tubing. A harder, thicker walled type is preferable. Both viton and Therban (and a few other hydrogenated nitrile rubbers) are compatibile with B100 and ULSD, but viton handles heat far better. Unfortunately, the manufacturers didn't seem to take that into account when choosing what type of tubing to use for those inter-injector lines. Hydrogenated nitriles are cheaper, which was probably the determining factor.

Thanks for the helpful info. A corroborating comparison of viton v. nitrile can also be found at www.oringswest.com. Both are rated the same (highest) for resistance to most oils, including soybean, although Viton is more heat resistant. Thanks Mike, soypwrd and MITBeta.

Chris How is it going with the return line issue? What material did you get and what was the source. I've only got about 1,000 miles on the 95 E300 with B100 and would like to keep updated on any other issues you may have. I know that Randall von Wedel has a 96 or 97 that he got earlier this year for B100 use but I have not heard of any problems from his end.