Biodiesel and rubber parts.
 

I am planning on purchasing an older 240D, and was considering running it on homemade Biodiesel, as I understand pure Biodiesel is hard on natural rubber components. I know that new fuel lines made of synthetic rubber can be installed easily, but i was wondering if anyone knew about any other rubber components in contact with fuel, and whether synthetic replacements can be found. Any Information would be greatly appreciated.

Think about all the used fry oil thats going to waste around LA, :eek: guess you HAVE been thinking..... Good Idea,... :) someone will know for sure but I was under the impression the early '70"s 240Ds used rubber that would be harmed by bio diesel so needed to be upgraded. Good Luck

Howdy,

The subject of biodiesel has been discussed to death over on the Volkswagen TDI forum. The main danger centers around the fact that biodiesel is very hygroscopic and can contain water. This can corrode you fuel system, but properly made and stored biodiesel shouldn't have water in it.

The other issue that is discussed alot is that biodiesel is a powerful fuel system cleaner. This is good obviously in that it keeps your injectors clean but does knock loose alot of junk when you switch over. There are some other differences such as higher cetane, better lubricity, much worse cloud point, lower energy content, and no sulfur that are discussed.

Check out the TDI site at:

http://forums.tdiclub.com/NonCGI/ultimatebb.php?category=3

Sholin

Mercedes 240 run well on biodiesel, on my 1984 300d 144,000 miles I havent changed the fuel pipes inside the car (have'nt need to)
BUT carry spare fuel filters, the inline one before the pump saves the cannister one (a wee bit!), also you will eventually have to clean out the nylon sock filter at the bottom of the tank I had to after 20K easy enough to do just make sure the tank is nearly empty before starting!!!!!!
Be prepared to change the rubber surround at the tank filler because if you spill bio it will dissolve.
In 30,000+ miles on bio apart from filters (which are a pain) it has been all positive, lower emissions being one big advantage

if its homemade as long as it is clear it should be OK

so good luck



Des

greetings,
I haven't ventured into the bio usage and alterations yet but its my understanding that its the methanol left in the solution from the removal of the ethers (de-esterification?) that attacks the rubber parts. I think the rubber hoses etc. have to be replaced with teflon or similar material. I'm sure the people who supply race cars that burn methanol will have the adequate substitutes.
cheers, mark

81 240d

I'll keep that filler surrond in mind, I had heard though that seals in the injectors in some cars could be attacked too though, and was wondering if anyone knew about that.