Adblue - refilling issues?

[DG1]

I wonder if the buyers of T6 panel and combi vans get the run down on these two issues during the handover process? There is less to cover with those.

The problem with Californias, especially Oceans, is there are so many things to know about concerning the control unit, water supply, gas supply, raising roof and bed operation, that there is a real risk of information overload when collecting your van—without all these issues to do with the engine in addition.

When we did our handover I reached a point where I couldn't take anything more in. This forum has been a fantastic resources to learn things in my own time.

 

[WelshGas]

If I have understood correctly, during the regeneration process, diesel is used to burn the soot and everything gets extremely hot. To keep things a little cooler, excess cool diesel pumped around to keep the regeneration process a little cooler, before this now hot diesel is returned to the tank, this causes the temperature of the diesel in the tank to rise.

This is all fine when there is a reasonable amount of diesel in the tank. However, if at the start of the regeneration process there is less than 1/4 of a tank, the regeneration process will not start because there is a danger that the temperature of the diesel in the tank will rise to a level where it will not be sufficiently cool to cool down the regeneration process. So when the tank is less than 1/4 full the next regeneration will be delayed until the tank is fuelled to above 1/4.

This will quickly develop into a major problem if you only ever refuel to less than 1/4 tank. It is not an issue if you regularly fuel to full and then run down the tank to less than 1/4 tank before refuelling as the regeneration will occur as soon as there is sufficient fuel to keep the regeneration process cool.

Not quit correct I’m afraid.
Diesel is Not used to cool the DPF during a regeneration.

Diesel fuel heats up as it passes around the Fuel system, due to friction and the high pressures generated by the fuel pumps etc:.
The excess fuel is returned to the tank to cool down. If the Diesel fuel gets too hot then it can begin to boil/vapourise which could cause severe problems with the high pressure fuel pump and fuel delivery to the injectors. Many Diesel Injector engines are fitted with fuel coolers. Apparently, the T6 engines have been designed/built without such a cooler, according to @Vw guru . Hence the need to keep a larger volume of diesel in the tank to cool the Diesel return flow.

 

[Jay586]

I wonder if the buyers of T6 panel and combi vans get the run down on these two issues during the handover process? There is less to cover with those.

QUOTE]

Nope, no handover for my panel van T6. Delivery was included in the price, so a lovely (but outsourced) bloke turned up with it at the house.

 

[Legin]

Isnt the upshot of all this rather simple. Im not in anyway defending VW inadequate design but the work around really is straightforward.
Add blue - go by the mfd and short fill it slightly.

Diesel - Its ok to run it right down but when refilling it the routine should be 3/4 tank plus. Personally I always fully refill anyway.

Oh and personal thanks to Guru, your invaluable to the forum keep it coming.

 

[MaxRed]

Found a research over 2 stroke oil and diesel: https://www.fuelexpert.co.za/2-stroke-oil-in-diesel-technical-study.php

 

[MaxRed]

Found a research over 2 stroke oil and diesel: https://www.fuelexpert.co.za/2-stroke-oil-in-diesel-technical-study.php

TL;DR: Not actually needed on modern engines and fuels and can decrease DPF lifespan.

 

[2into1]

An summary from @MaxRed ’s link above......
The results of the study support a view that the practice of dosing diesel with 2-stroke oil is surprisingly ineffective in terms of lubricity and cetane improvements. Engine performance, fuel consumption and emissions were also unchanged; however the use of 2-stroke oil in diesel is potentially harmful to modern diesel injection equipment. Trace amounts of zinc, an element which is found in most 2-stroke oils, are well known to cause injector nozzle fouling and the study measured high levels of injector fouling when the test engine was running on diesel dosed with 2-stroke oil. While the oil industry may not mind the additional revenue from the sale of 2-stroke oil with each tank of diesel, this study demonstrated that it is not in the best interest of the user to do so.

 

[Loz]

Isn't 2 stroke likely to produce more soot and increase the frequency of dpf regenerations?
I have a job lot of millers diesel which is mainly cetane which adds the lubrication.

 

[ArunAlec]

Assume used cooking oil from the chippy is out of the window then?

 

[Eber123]

Good afternoon,

Thank you Tom, the penny (finally) dropped. With your explanation even I got this now.

I believe my problem was that, in my opinion, the regeneration process only happens every blue moon.

Regards,
Eberhard

 

[Jay586]

Isnt the upshot of all this rather simple. Im not in anyway defending VW inadequate design but the work around really is straightforward.
Add blue - go by the mfd and short fill it slightly.

Diesel - Its ok to run it right down but when refilling it the routine should be 3/4 tank plus. Personally I always fully refill anyway.

Oh and personal thanks to Guru, your invaluable to the forum keep it coming.

Don't disagree, just wish it had been flagged up to me.

A family member, sadly not blessed with much sense, has killed a couple of cars with chip oil. No telling him tho...

 

[Amarillo]

Not quit correct I’m afraid.
Diesel is Not used to cool the DPF during a regeneration.

Diesel fuel heats up as it passes around the Fuel system, due to friction and the high pressures generated by the fuel pumps etc:.
The excess fuel is returned to the tank to cool down. If the Diesel fuel gets too hot then it can begin to boil/vapourise which could cause severe problems with the high pressure fuel pump and fuel delivery to the injectors. Many Diesel Injector engines are fitted with fuel coolers. Apparently, the T6 engines have been designed/built without such a cooler, according to @Vw guru . Hence the need to keep a larger volume of diesel in the tank to cool the Diesel return flow.

Thanks @WelshGas.

If there is no heat exchange between the fuel and DPF why is running the tank below 1/4 full a problem particular to the DPF regeneration and not a constant problem?


Follow my blog: www.au-revoir.eu

 

[WelshGas]

Thanks @WelshGas.

If there is no heat exchange between the fuel and DPF why is running the tank below 1/4 full a problem particular to the DPF regeneration and not a constant problem?


Follow my blog: www.au-revoir.eu

From my reading of the system, the DPF when regenerating uses fuel at a faster rate during regeneration. At low fuel levels there could be insufficient fuel in the tank to cool the hot diesel returning from the Fuel/injector System. If the DPF then starts regenerating using fuel at a faster rate than during normal driving then you can arrive at a situation where the tank fuel level drops to a point that there is negligible cooling effect and the diesel fuel temperature starts rising to a point that it can vaporise and cause problems in the pressurised part of the fuel system.

 

[Amarillo]

From my reading of the system, the DPF when regenerating uses fuel at a faster rate during regeneration. At low fuel levels there could be insufficient fuel in the tank to cool the hot diesel returning from the Fuel/injector System. If the DPF then starts regenerating using fuel at a faster rate than during normal driving then you can arrive at a situation where the tank fuel level drops to a point that there is negligible cooling effect and the diesel fuel temperature starts rising to a point that it can vaporise and cause problems in the pressurised part of the fuel system.

Ok that makes sense. It is a greater flow of diesel through the system during the regeneration which causes the temperature of fuel in the tank to rise not heat exchange with the very hot DPF.


Follow my blog: www.au-revoir.eu

 

[WelshGas]

Ok that makes sense. It is a greater flow of diesel through the system during the regeneration which causes the temperature of fuel in the tank to rise not heat exchange with the very hot DPF.


Follow my blog: www.au-revoir.eu

Almost. There is always Hot Diesel being returned to the tank, but when a Regeneration occurs, fuel consumption increases so that the tank fuel level will fall even quicker. Not a problem unless the Tank fuel level is already very low as the remaining volume of fuel, following regeneration, is insufficient to cool the returning hot fuel, adequately.

Don’t forget the diesel in the tank could have a temperature of -10c in a Norwegian winter or +40 c in an Italian summer. So 10L of diesel in the tank could be enough in winter, but not summer.
I think VW stating 1/4 tank are attempting to cover all bases.

 

[Jay586]

Well, after 6 pages of informative posts, I now have an answer for my own particular issue. It's a temperature sensor issue, which requires a software upgrade, which is not available as yet...

 

[Meoncoast]

More by luck.
1. I fill up with fuel when I hit 1/2 empty.
2. I fill up (adblue)when ordered to by the van - and have only ever added 10litre from a bottle.

 

[Jay586]

Adblue pump info bump.

 

[Amarillo]

It seems nuts that VW don't design the AdBlue tank so the pumps cut out at the correct refill level.

I have just refilled with AdBlue.

MFD said max refill 9.50 litres. Perhaps recklessly, given the sage advice from @Vw guru, I decided to fill to cut out. I inserted the nozzle fully, and it cut out at 9.60 litres. It will take two or three refills like this to convince me that this is design not coincidence, but this one refill so close to the recommended maximum is sufficient for me to think it more likely than not to be a design feature.

 

[Jay586]

And meanwhile, my warning light reappears occasionally. It needs a software fix, as yet unavailable...

 

[VW Guru]

And meanwhile, my warning light reappears occasionally. It needs a software fix, as yet unavailable...

Hi it could be months and months away the factory no longer tell us as dealers the eta of a software fix. The v6 amaroks have been waiting over a year now for a software update.

 

[cbdubs]

Shell V power for me every time. I heard that supermarket diesel has bio diesel in it to make it cheaper but that's not good for VW engines apparently - don't know how true that is but not prepared to take the risk.

Also, as an aside, if you are using a K&N air filter, clean the oil from it and run it dry. Apparently, the oil K&N use is drawn in on the intake side and can damage the MAF sensor. Again, don't know how true that is but just repeating what I heard or read somewhere.

 

[Loz]

Shell V power for me every time. I heard that supermarket diesel has bio diesel in it to make it cheaper but that's not good for VW engines apparently - don't know how true that is but not prepared to take the risk.

Also, as an aside, if you are using a K&N air filter, clean the oil from it and run it dry. Apparently, the oil K&N use is drawn in on the intake side and can damage the MAF sensor. Again, don't know how true that is but just repeating what I heard or read somewhere.

Don’t start the fuel debate.. all fuels have to have bio in them now...

 

[Jabberwocky]

This thread contains vital information for all Cali owners that have a need for Adblue. (That's why I have changed the thread title so folks can find it more readily.)

I just looked at the owners manual and look what I found. Page 270 of the owners manual says......



So it seems the first click is good and that means you should just fill up your adblue in the same way you top up your diesel. (This is what I have done in the past and did today)
@Vw guru I would be most interested in any comments you have in light of the above and all the preceding comments. Thanks in advance.

 

[VW Guru]

This thread contains vital information for all Cali owners that have a need for Adblue. (That's why I have changed the thread title so folks can find it more readily.)

I just looked at the owners manual and look what I found. Page 270 of the owners manual says......

View attachment 41675

So it seems the first click is good and that means you should just fill up your adblue in the same way you top up your diesel. (This is what I have done in the past and did today)
@Vw guru I would be most interested in any comments you have in light of the above and all the preceding comments. Thanks in advance.

Hi @Jabberwocky i actually read this the other day and nearly choked on my coffee the statement totally contradicts what we as technicians have been told by vw to tell our customers and also what we have learnt from working on the systems. I think there is another statement in the manual that states always fill up according to the amount on the instrument cluster. That also concerns me as I had a vehicle in today that said fill with 3 gallons which is 13.6 liters 600ml over the maximum of the 13 liters and would of caused the system to have issues, once I changed the dash to liters and km it calculated it as 11.5 liters required which seemed more plausible so I feel there maybe a software error in the adblue calculation on the dash. My advice would be if filling up from a proper pump like a fuel pump type pump then fill it to it clicks off as you do and don’t add any more. If filling from a bottle then once the display shows 1500 miles remaining put in 10 liters and the tank will be somewhere near full but sat just below the max and not cause any problems.