Different Infomation in Liter vs. gramm about Oil Ash Residue

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secret007
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Different Infomation in Liter vs. gramm about Oil Ash Residue

Post by secret007 » Sun Jun 27, 2021 10:49 pm

Hello everybody,

A few days ago I also bought the Pro version of the VAG DPF app to find out more about the condition of the DPF.

My vehicle: Skoda Superb 2 Kombi (3T5) 4x4 2.0 tdi, 125 KW, year 2011, engine code CFGB, with 259,000 km. I have been the third owner for 2 years and have only driven approx. 10,000 km in this time (Long haul / short haul 50/50).

On Friday I also experienced regeneration for the first time. According to the app, the last regeneration was just over 200 km ago. The regeneration took a good 30 minutes with normal driving on the country road and went up to 25%, which is apparently normal.

But I have one more question about the Oil Ash Residue: This is shown here as 0.18L (without any further% specification ???). In the Skoda documentation, however, the maximum ash value is given as 70 grams.

What does the 0.18L mean for me now? How full is the DPF? Is there a way to convert that to grams?

I hope someone here can help me.
Many Thanks

greetings
Roland
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admin
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Re: Different Infomation in Liter vs. gramm about Oil Ash Residue

Post by admin » Mon Jun 28, 2021 8:55 am

The app shows the oil ash percentage only if it finds the oil ash limit in the reading data, in your case this value isn't available.
But if you've found it in the service manual, you can easily calculate the clogging considering that the ratio between liters and grams is 400.
To obtain grams from your liters value, you have to multiply by 400 so 0,18 l = 72 grams.
I use the factor 400 because all the engines, in which I found both grams and liters values readable from the ECU, have this ratio, but I can't guarantee this value is valid for all TDI engines, consider it as "to be verified".

Usually the DPF life is between 250.00 and 300.000 Km depending on the drive style and environment, I think your DPF is near the end of its life.
The maximum value isn't a mandatory deadline, I've seen many engines running fine with oil ash over the maximum, but obviously the filter performance is reduced and you should see this with frequent regenerations. The oil ash in fact reduces the internal filter volume and the soot mass fills it faster.

You should consider a filter cleaning or replacing in the near future, but give a check to the regenerations frequency to confirm all my assumptions.

secret007
Posts: 2
Joined: Sun Jun 27, 2021 10:33 pm

Re: Different Infomation in Liter vs. gramm about Oil Ash Residue

Post by secret007 » Mon Jun 28, 2021 11:49 am

Many thanks for your quick response and detailed explanation :-)

The big question at the moment for me is:

Is it possible to use the car for our planned vacation trip to Croatia now (in summary 2500 Km) without cleaning or changing the particle filter before?

What is your opinion?

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admin
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Re: Different Infomation in Liter vs. gramm about Oil Ash Residue

Post by admin » Tue Jun 29, 2021 2:49 pm

I don't have experience on that and there aren't official documentations available for us. What I can report is that some users confirmed me that their cars run fine also with the oil ash over the limit, but this can't be an absolute guarantee.
Personally I think that the limit is just an indication that must be present, but doesn't correspond to a unusable filter. It's just an indication for the service guys to understand when it's time to recommend the filter replacing.
What you can verify is the regenerations frequency and evaluate if the kms between them are reasonable. The current filter condition won't change so much after 2500 kms, I think.

These are my personal considerations, if you want to be sure, you should ask to an expert.

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