Audi A3 2.0 tdi.

[Oilybloke]

A mate of mine has just started using my fuel, running 70% bio, in his 2011 Audi. Fuel filter warning light has come on, and it has gone into 'limp' mode. I have several cars of this age running B100 with no problems at all. Apart from a filter swap, is there anything else I should look for?

Cheers!

[julesandtash]

I would definitely go for a filter change first and take it from there.
When I bought the Allroad in Leicester, I drove it back on B30 ish (lots of dino and some of NigelB's finest bio).
No problems there.

Nearly empty when home so filled it with B100. It clogged a filter within 50 miles to the point it would barely run.
Changed the filter and that one lasted about 100 miles.

Changed filter again and now it has done about 400 on that one and still going strong.

Sometimes they just do play up a bit on first changeover, I guess 130K miles on dino had put plenty of stuff in the fuel system that the bio picked up.

[nigelb]

It's really strange this relationship between miles covered on dino and the blocking of filters when changing to biodiesel.

My latest passat, that I've had since the back end of September, is still on the same filter. I've noticed no loss of power or performance and the car has been on bio for the last 4K miles.

No noticeable changes were experinced in the Mondeo, the first Passat and my wifes golf.

The only filter issue I've had was one that blocked/collapsed after running for about 20K

[Jamesrl]

We've changed 6 vehicles over to bio, b100 from day one, and never had a filter block because of it.

[Jmg]

I've never had a bio motor block a filter yet but half of my veg cars blocked filters on a regular basis for the first 2/3000 miles.

Then again, I actually filter my bio, my veg only ever went through a pillowcase and settled for a bit

[Glycer-rides]

It's really strange this relationship between miles covered on dino and the blocking of filters when changing to biodiesel.

My latest passat, that I've had since the back end of September, is still on the same filter. I've noticed no loss of power or performance and the car has been on bio for the last 4K miles.

No noticeable changes were experinced in the Mondeo, the first Passat and my wifes golf.

The only filter issue I've had was one that blocked/collapsed after running for about 20K

Same with my last five motors. No cleaning effect noticed.
The Mercs I've had all suffered quickly on change over to bio due to the original fuel pipe O rings finally giving up and inducing air leaks between the lift pump and the IP.

[Oilybloke]

Many thanks all. It's one of those weird things.......I know it's not the fuel, as none of my other regulars have had problems from that batch. Or could I be wrong in thinking that?

[Manfred]

Not that I can afford a newish car but as some mid 2000 cars are fitted with a dpf how do they cope with Bio. I hear they can get blocked with Dino on constant short town runs.

[1958steveflying]

Many thanks all. It's one of those weird things.......I know it's not the fuel, as none of my other regulars have had problems from that batch. Or could I be wrong in thinking that?

If his fuel filter that blocked had not been changed for a very long time prior then not really too surprising.

[Tony]

Most likely not the bio but all the diesel crap in his fuel system that is has dislodged.

Both the Serena and Largo (touch wood) have been no problem swapping over from dino to bio.

[Oilybloke]

It transpires that the warning light was the DPF (have I got that right?) and the manual recommended giving it an Italian tune-up. A bit difficult over here what with 40mph speed limit..........

[Julian]

40 mph in first or reverse should do it!

[greasemonkey]

Goes it have a tow hitch? Sticking a heavily loaded trailer on and pulling it up a few hills does wonders for a diesel motor.

[1958steveflying]

It transpires that the warning light was the DPF (have I got that right?) and the manual recommended giving it an Italian tune-up. A bit difficult over here what with 40mph speed limit..........

  The important thing with Dpf regeneration is that you follow the correct procedure ! On most you have to maintain 30mph all the while the light is on, the exhaust has a pressure sensor before and after the Dpf, all the time the pressure difference is to great the Ecu will call for regen. The regen process injects fuel into the engine late so it does not burn off in the combustion process but burns off in the Dpf. Everytime you stop the process it has to restart again which just keeps blocking it more.
  It would help to get the highest % of Dino in it as it burns off the particles better than Bio. As Greasemonkey has said loading the engine to get the highest exhaust gas temperature is a sure way of not only helping it through the regen process but done periodically it will stop it blocking in the first place. Even turning on all the electrics will load the engine via drag from the alternator.
  You cannot poodle a diesel with a Dpf around the engine needs to be working.

[Greenchef]

My wife's latest car is an audi a4 tdi on a 59 plate. It's now done 10k on b100 with no dpf problems or indeed fuel filter changes.
Having said that the bulk of those miles are motorway work and the school run is across the Forest of Dean so mostly working miles.
To be honest I think if I was buying a newish car and only going to potter around in it. (This hurts me to say it!) I would probably go petrol and LPG it and run it until it dies!