"Don't fill with biodiesel at the supermarket..."

[romeogolf]

A colleague has a diesel Audi A3 - I think it's a 59 plate model (all she can tell me is that it's S-line and it's black). This weekend she had the exhaust system looked at as a fault light appeared on the dash.

Apparently, the garage told her not to fill up at Tesco or Sainsbury's because they use biodiesel and this "damages the sensors" - She should only fill up at Shell or BP.

Besides the issue of someone driving 4 miles to work and back in a diesel, is there any truth to this claim that (a) the supermarkets sell biodiesel and (b) this damages the vehicle?

I smell bullst but the PH collective may be able to educate me...

[berlintaxi]

romeogolf said:

Besides the issue of someone driving 4 miles to work and back in a diesel,

That'll be the issue right there, bullst on the fuel claims.

[trickywoo]

4 mile trip is the problem.

My understanding is that bio actually burns cleaner although there is some debate about the overall supermarket vs big brand fuel additives and their benefits.

For a regular 4 mile trip a diesel, particularly a new one, is the absolute worst choice.

[kambites]

I was under the impression that all road fuels sold in the UK had to contain a certain percentage of bio-fuels?

[Fastdruid]

I'd tentatively suggest it's bullst to try and deflect blame and avoid any claims they missold a diesel for unsuitable use.

All diesel in the UK except maybe from a few specialist outlets will contain up to 7% biodiesel.
There were a few supermarkets doing very high biodiesel % blends but pretty rare. I'm not sure if any still are.

Edited by Fastdruid on Monday 24th July 09:45

[Mr MXT]

All diesel in the U.K. Contains bio (5% IIRC)

[r11co]

kambites said:

I was under the impression that all road fuels sold in the UK had to contain a certain percentage of bio-fuels?

This.

Fastdruid said:

I'd tentatively suggest it's bullst to try and deflect blame and avoid any claims they missold a diesel for unsuitable use.

This also.

The stock-fuel blend sold in any geographical area is identical regardless of brand. Storgage and/or additive issues are the only variations, but that is not an issue related to whether it comes out of a tank in a supermarket car-park or a dedicated fuel station.

[steveo3002]

yep i always head to a tyre and exhaust center when i need an expert opinion on fuels

[anonymous-user]

Fuel arguments aside, the problem here Is the massive 8 mile round commute, be prepared for the dpf to clog right up shortly.

[alephnull]

Four miles? You'd cycle that no?

Wait, this is PH.....rallycross bike?

[cuprabob]

You should ask her if the Emissions Update has been done to the car by the dealer as quite a few VAG owners have issues as described after the update.

Also, 4 mile journeys in a diesel is just asking for trouble, as already said.

[Sheepshanks]

DSGbangs said:

Fuel arguments aside, the problem here Is the massive 8 mile round commute, be prepared for the dpf to clog right up shortly.

I don't know if all VAG cars use the same system, but wife's Tiguan does an active regen whenever it needs to and the car is programmed to do one every few hundred miles regardless. You can go on a long motorway trip and then next day it'll active regen.

On the fuel, if the car is only doing low mileage overall then I'd be minded to use the Shell V-Power stuff. Who knows whether it really makes a difference but for low mileage the cost difference isn't significant and you're giving the car the best chance you can.

[CraigyMc]

Sheepshanks said:

DSGbangs said:

Fuel arguments aside, the problem here Is the massive 8 mile round commute, be prepared for the dpf to clog right up shortly.

I don't know if all VAG cars use the same system, but wife's Tiguan does an active regen whenever it needs to and the car is programmed to do one every few hundred miles regardless. You can go on a long motorway trip and then next day it'll active regen.

On the fuel, if the car is only doing low mileage overall then I'd be minded to use the Shell V-Power stuff. Who knows whether it really makes a difference but for low mileage the cost difference isn't significant and you're giving the car the best chance you can.

It can't do a regen if it's cold, during a 4 mile journey it will be all the time.

Forget DPFs for a second. That car never gets its *oil* up to temperature.

[KTF]

I dont know why dealers use the type of fuel as a get out clause. If you told them you only ran it on V-Power would they then say that caused the issue as well?

[5harp3y]

its the type of journey, not the fuel.

that sort of commute only really suits a petrol engine

[TooLateForAName]

5harp3y said:

its the type of journey, not the fuel.

that sort of commute only really suits a petrol engine

Actually that is prime EV use.

[anonymous-user]

CraigyMc said:

Sheepshanks said:

DSGbangs said:

Fuel arguments aside, the problem here Is the massive 8 mile round commute, be prepared for the dpf to clog right up shortly.

I don't know if all VAG cars use the same system, but wife's Tiguan does an active regen whenever it needs to and the car is programmed to do one every few hundred miles regardless. You can go on a long motorway trip and then next day it'll active regen.

On the fuel, if the car is only doing low mileage overall then I'd be minded to use the Shell V-Power stuff. Who knows whether it really makes a difference but for low mileage the cost difference isn't significant and you're giving the car the best chance you can.

It can't do a regen if it's cold, during a 4 mile journey it will be all the time.

Forget DPFs for a second. That car never gets its *oil* up to temperature.

I agree, public transport would be a far better option all things being equal.

[MorganP104]

The car in question here needs a proper Italian tune-up, ideally over a journey of 50 miles or more.

Once its been ragged to within an inch of its life, plug in a fault code reader, reset any error codes, and see what happens.

I've done this a number of times over the years, with some success.

PS: Even if it doesn't work, it's fun.

[Sheepshanks]

CraigyMc said:

It can't do a regen if it's cold, during a 4 mile journey it will be all the time.

Ours does. It's typical journey is 3-4 miles. If you interrupt a regen it starts again next time the car is used. I did some research before we bought it and owners with similar use patterns reported no issues.

CraigyMc said:

Forget DPFs for a second. That car never gets its *oil* up to temperature.

Interesting in the Tiguan (and again, I assume common in VAG cars) the water temp will display 90C very quickly. But it's ECU generated - it's not the real temp. It can display the oil temp too and that takes about 15 miles to get to 90C.

[cuprabob]

If it starts a regen and it doesn't finish it, the fans run on for around 5 mins and it will start the regen on the next journey.

It will force a regen around every 700 miles.

You can also force a regen with driving at a constant 2,500 rpm or thereabouts.

Edited by cuprabob on Monday 24th July 11:13