You probably don't even have to mention biodiesel.

Hard to say what it would fetch, but I'd start with 8-9K and include OBO. I wouldn't pay 8K for it, but someone else might. I bid on a 300TD on ebay last year, up to about 6500, after test-driving the car. It went for over 9500, probably to someone who didn't test-drive it, but it drove just fine. It had fewer miles than yours, but don't let that stop you from trying.