running petrodiesel in a 300D that's been on bio... - PeachParts Mercedes-Benz Forum

sleepstar · #1 02-14-2012, 02:28 AM

i've recently purchased a 1981 300D that was run on B100 for the last five years. i'm wondering if switching back to petro for the time being will be problematic. i'm especially concerned about the injection pump seals. apparently bio will cause the seals to swell, and the petrodiesel may cause them to shrink back? i can run a mix for the time being, but biodiesel here is about 50 cents more per gallon than B5.

charmalu · #2 02-14-2012, 02:42 AM

Shouldn`t hurt anything. I would say if the previous owner ran B100 for 5 yrs, then the rubber bits have been changed to Viton, or there would have been some leaks from the Bio.

Charlie

MB300Dave · #3 02-14-2012, 07:40 AM

Quote:

Originally Posted by sleepstar

i've recently purchased a 1981 300D that was run on B100 for the last five years. i'm wondering if switching back to petro for the time being will be problematic. i'm especially concerned about the injection pump seals. apparently bio will cause the seals to swell, and the petrodiesel may cause them to shrink back? i can run a mix for the time being, but biodiesel here is about 50 cents more per gallon than B5.

By running BioD, the previous owner saved wear & tear on your IP & injectors not to mention kept everything clean. BioD is a cleaner & a great lubricant. I would run at least a B5 or if you go back to D2. I run an additive like Power Service Diesel Kleen, 1oz-3gal mix, or you can use something similiar.

BTW, you get the best bang for the buck at B20.

Dave

sleepstar · #4 02-14-2012, 11:48 AM

thank you, that is great news. B5 is easy to get around here, as is B100, but i thought B20 was unavailable nearby. however i've just discovered a station i previously wasn't aware of on biodiesel.org (i guess its a unocal with a propel biofuels pump) since i need to fill up anyway i'm going to go by and see if they really have B20.

PackerEdgerton · #5 02-14-2012, 11:59 AM

Quote:

Originally Posted by sleepstar

thank you, that is great news. B5 is easy to get around here, as is B100, but i thought B20 was unavailable nearby. however i've just discovered a station i previously wasn't aware of on biodiesel.org (i guess its a unocal with a propel biofuels pump) since i need to fill up anyway i'm going to go by and see if they really have B20.

You can always fill your tank partially with #2 Diesel and then finish the fill at a B100 station (or if they are the same station, it will be easy). You can mix in any ratio.

Sincerely,

PE

P.S. I have a truck that has been running B100 for nearly 50K miles. It runs much better than before I switched. Since I have been running B100, I did have to change the filters about 3x. (I also 'ramped up' the biodiesel, B20, then B50, then B75 and finally B100 over 4 tankfuls, all while carefully checking the filters and lines) The filters did gunk up pretty quickly at first. Now they are pristinely clean every time I change them out.

I also had some blowby on the truck, and with regular oil changes (I use Delo400 15W-40) every 3K miles and B100, the blow-by is totally gone, and the truck definitely has more power. Assuming your rubber seals are OK, I think it is a very good thing. I do buy commercial ASTM spec biodiesel.