We had the dealer install a new fuel filter in a 2005 Diesel Passat. This car has been running on biodiesel for about 1 year without even a hiccup.

Drove the vehicle home and left it in the garage for 2 days. Wouldn't start. Just reved.

Had it towed to the dealer. They claimed I had contaminated fuel (which I explained was biodiesel. I suspected an air leak or bad o-ring but they said the only thing they would do is drain the fuel, put on a "non-contaminated" fuel filter and then begin the diagnosis. Of course this was going to cost me another $325.

I chose to have it towed (again) to my normal mechanic who understands bio. He replaced o-rings toped off the filter and it ran just fine.

BUT...a few hours later is died again. It did restart on its own after cranking for 10 secs about 4 times. Drove it back to him and he is trying to figure out what the fuel delivery problem is.

Any suggestions? Thanks.

Well it turned out that the dealer wasn't the cause. Probably whoever would have changed it would have triggered the problem. Turns out that my one of my containers that holds the biodiesel has some dried floor polish in it (looks like cellaphane). I thought I had cleaned them real well but apparently not and some of this crud had gotten in the tank.

Likely it settled on the bottom and wasn't causing any problem. When the fuel filter was installed and the fuel pump got busy filling it it sucked some of this stuff onto the screen on the fuel transfer pump. That was starving the engine, etc. etc.

Pumped out the fuel, cleaned the tank and the fuel pump screen. I also checked every container, too.

Back on the road and hopefully will be trouble free.

It was just so interesting how the dealer reacted to the idea of biodiesel in the tank.