Slow drip of diesel

We have a 2003 VW diesel jetta wagon with 63K miles. Always ran this on ~ 100% biodiesel. Recently (a month ago), the car began starting with difficulty; but, eventually starts. I see lots of air in the clear line near the filter - then lots of bubbles after the car starts. It runs fine. Just noticed a slow drip of biodiesel on the high-pressure side of the pump (~ every 20-30 secs) when the car is running.

Is there anything that can be done to repair this (short of a diesel pump overhaul)? Thanks in advance!

Stop by www.tdiclub.com and there you will find the answer to any VW diesel question.

My guess is you have two problems. That slow leak and those bubbles, which also may be a leak indicator. A few small bubbles are OK on most TDIs but lots need to be addressed unless you want continued problems starting.

As I recall VW does not recommend over 20% bio on your engine, but I believe a lot of people due run more without problems.