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.