Idle Speed

[Wardy]

My 2012 TD1340 Multivan which has covered only 3000km idles at approximately 850rpm but occasionally this rises to 1000rpm (without the A/C on). This seems to be a little on the high side to me.

I have called the local VW dealer and was told that this was quite acceptable as the idle speed could be anywhere between 800 and 1200rpm.

I would welcome any comments.

[Transporter]

The one of the reason could be that the DPF is regenerating at no longer than in 1000km intervals, but it could be more frequently, depending from the conditions, like your driving, the length of the trips and so on.

[Wardy]

The vehicle is used mainly locally for short trips with a longer trip (speeds in excess of 70kph for more than 30minutes) perhaps once a week.

Excuse my ignorance but are you saying that the increased idle speed is when the DPF is regenerating?

[Transporter]

Yes, so when it is regenerating keep the RPMs above 1600 while driving, the regeneration process usually tekes 15-20 minutes.

[Sunny43.5]

From a VW owners manual
DPF light symbol:-
Diesel Particulate Filter has become saturated with soot. :- Drive for approximately 15 minutes in 4th gear (manual gear box) or select D (automatic gear box) at a speed of at least 70km/hr (45mph). Please observe any speed limits -> (Red triangle box). Go to a qualified workshop if the light still does not go out.

From the Red Warning Box on Page 279
Please observe legal requirements if cleaning the diesel particulate filter when in traffic.
-Following driving recommendation only if visibility, weather, road and traffic conditions are suitable.
-Do not endanger other vehicles on the road.

Now in the information box (below warning box) it also states:
If the indicator lamps, DPF, Engine light or EPC are lit up, fuel consumption may be higher and engine performance reduced.

On the bottom of the page Volkswagen Recommends that to assist in the combustion process that you avoid only making short journeys.
-Using only low sulphur diesel.
-Never use petrol or heating oil.
-Never use bio-diesel. It is permissible to use manufactured mixed biodiesel within the scope of EN 590.
-Never allow the tank to run completely dry.
-Do not over fill engine oil.

To minimise blockage of the diesel particulate filter, the engine speed in vehicles with an automatic gearbox may increase slightly in order to automatically initiate cleaning process of the diesel filter. The indicator, however, will not light up.
I am not in favour of a system that seems to tell you not to drive short trips as it will cause problems surely VW could have come up with something better so the driver is not having to do this regen process . From research it seems that to avoid blockage the exhaust needs to be at least 200 degrees to burn off the soot by itself . So the occasional thrash is needed Hmmmm

[Transporter]

I am not in favour of a system that seems to tell you not to drive short trips as it will cause problems surely VW could have come up with something better so the driver is not having to do this regen process . From research it seems that to avoid blockage the exhaust needs to be at least 200 degrees to burn off the soot by itself . So the occasional thrash is needed Hmmmm

That temperature should be more like 350 degC , also most of the drivers will not know that the DPF is regenerating and possibly will never experience the problem with it. Our V6 TDI Touareg is 6 year old and my daughter who drives it 99.9% of the time never noticed the DPF regenerating.

Using the suitable fuel additive may help extend the life of the DPF by reducing the soot amount.

[Wardy]

Is there any particular diesel additive that is recommended either by VW or from the experience of members of this forum? If so with what frequency should it be added?

[Sunny43.5]

Or this T5 DE-DPF pipe, T5 dpf pipe

[Transporter]

Is there any particular diesel additive that is recommended either by VW or from the experience of members of this forum? If so with what frequency should it be added?

I'm using Moreys Diesel Smoke Killer and Liqui Moly Clean & Boost.

[Transporter]

Or this T5 DE-DPF pipe, T5 dpf pipe

Which is ilegal in AU, it doesn't matter that it may be tolerated in UK, so becareful if you go that way.