how to know if car has rubber seals in fuel system?


I would eventually like to purchase an older Mercedes diesel and install a WVO kit. I have read that older diesel engines use rubber seals and that biodiesel, and maybe WVO?, can cause them to deteriorate more rapidly. Can anyone tell me how to know if an engine has rubber seals vs viton or whatever the newer material is? Also, is it only the fuel line connections that would need to be replaced or are there gaskets and other seals involved? How big of a deal is it to change all of that out? I'm mechanically inclined but I don't want to get into tearing down an engine or anything too labor intensive. Also, I don't want to end up spending lots of $'s on seals. Any advice is appreciated.


Hi Henry, if you would like

Hi Henry, if you would like the nitty gritty purchase a Haynes manual for likely car you want and it has a schematic of the fuel system including lines. Anything prior to the late 90s will have natural rubber gaskets and seals where the meatal fuel lines that run under the car attach to the fuel tank. High concentrated biodiesel like B50 or higher will melt rubber fuel lines very quickly. I have seen B100 gooify line in a day. Under the hood there are rubber fuel lines that run from these small metal lines (one is a return line to the tank) to the fuel pump,filter and fuel injectors. Its not hard to replace them with syntetic line just kind of dirty and nasty from the diesel that will spill out. I would recommend starting from the tank (the lowest point in the system and draining the whole system first so as to not continually spill fuel from the lines. A friend passed the link below along to me for synthetic lines. My '85 300D mercedes needed about 15' with some to spare for mistakes and as spare. Good luck. JK

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