D5 (2005 on) Longer runs but more DPF regenerations - underlying issue?

[Proghound]

I have the D5 180 in my 2008 C70. It had 20k on when I got it 17 months ago but I've averaged about 1k per month, so it's now done 37k and just about fully loosened up.

Last year was I commuting 8 miles each way to the next town and back, in light to medium traffic. I also did regular longer runs of 15-50 fairly gentle miles at 45-65mph. I used to get DPF regeneration about every 400-450 miles. If one didn't complete, it would restart the next time the engine got warm enough.

Now I'm commuting 21 miles each way, mostly A-B roads, small towns/villages every few miles but basically always moving. I still do the same other regular runs also. So I almost never do any journey shorter than 15 miles - ideal conditions for the DPF you'd think.

What I find strange is that I'm now getting regenerations more often, at about 200-220 miles. But if they start too close to my destination to complete, they often don't restart, if the engine gets to cool down fully before its next use. Then it will do 180-200 miles to the next regeneration. I also had a 180 mile interval after a completed regeneration, which included 120 motorway miles at 65mph, but also 45 minutes of M25 crawl.

According to the manual, it's within tolerances - every 300-900km or roughly 185-560 miles - but only just. No messages about the soot filter have ever come up. I was wondering, might the DPF be hiding an increase in smoke output? Or is the system simply working as programmed?

I have already thought to run a bottle of injector cleaner through, adding it to a low fuel level and having a blast down the motorway for 20 miles while it was concentrated, before filling up. I now see about a 5% increase in economy (over 50mpg measured brim to brim), but no difference to the regeneration interval.

Any thoughts/comments, gentlemen?

[5cilinder]

How do you know its regenerating?
watching the torque-app just like i am?

The regeneration strategy is as follows:
If the speed remains below 85 km/h regeneration intervals become larger up to 1000 km (new dpf with no ash)because the regeneration condition is not favourable
if highwayspeeds are reached between 500 and 1000 km the regeneration interval is shorter because of the favourable condition (less after injection because of higher engine baseload)
Its not only the interval wich counts but also the regeneration duration
Normally if my interval is shorter also the regenaration duration is shorter
The regeneration not restarting after a short interval hints at a favourable condition
If the regeneration had started at a high interval then always the regeneration will be initiated the first drive after highway or not

Check next time if the regeneration is started after a short interval if it was initiated at 55 miles/hour or faster and the duration of the regeneration
If the regeneration duration is shorter after a long interval where no speeds above of 55 miles/hour where reached everything will be function ok

If the dpf mileage becomes high with more ash in it those 500 and 1000km distances become shorter

Also
If you use some kind of premium diesel with gtl (gas to liquid) component in it
it creates less soot but some "super soot" wich burnes at 650 celcius instead of 550/600 celcius
Then the first time when its used the first regeneration interval will be larger but when the supersoot is created the regenerations after will be shorter because of unburned "supersoot"

[Proghound]

Originally Posted by 5cilinder

How do you know its regenerating?
watching the torque-app just like i am?

Thank you for a detailed response. I only have a couple of minutes right now so I will just answer your question before I go away and digest everything you've told me.

I don't have a smartphone so I use the trip computer to tell me when the DPF is regenerating.

I reset my average MPG every time I completely fill the fuel tank - that's most times when I fill up. Nearly every journey I make is one I do regularly, so I know where the average MPG figure tends to rise and where it tends to fall (this has a lot to do with where the hills are!). When it drops unexpectedly I look at the instantaneous readout. Recently I'm driving around most of the time with the instantaneous readout showing, to keep an eye on it.

The real test is what happens when you come off the throttle and the instantaneous MPG figure goes back to 99.9. Normally this will take 2-3 changes of reading, and the last one will be a big jump e.g. from 40-50MPG or often lower. But when it takes 5-6 changes, and goes through figures in the 70's and 80's MPG before it gets to 99.9 then I know it's injecting extra fuel to regenerate. (I don't think this method would work in a car with an EOLYS DPF).

[5cilinder]

Well thats a way to do it with the risk to miss one or get missleaded by headwind & consumption

I don't have a smartphone

Time to get a cheap (second hand)android one also handy for free up to date navigation and free faultcodereading
Earns itself

Get the torque app and an elm 237 monitor the egr valve and the throttle
If the egr valve closes and the the throttle is closing up to 1/3 you know its regenerating
Also the lower turboboost and the lower railpressure confirms regeneration
After regeneration you reset one of the mileagecounters to know when aprox a regeneration will occur to pay attention
Also in the torqueapp you can make "alarmrules" wich can give a signal if all the conditions are met or finished

More accurate/simple will be the catalyst temperature but that one is not (yet)retrievable in the sensor list
Also the readout in catalysttemperature is handy in activating passive regeneration with higher temps on the highway
Soon ill will do all the possible obd requests bruteforce to see if i can obtain a list with responses for the missing sensors in the list and create them manualy in torque

Also torque is a very effective faultcode reader for engine related trouble codes, always handy and cheaper than the stealer

[Proghound]

Originally Posted by 5cilinder

The regeneration strategy is as follows:
If the speed remains below 85 km/h regeneration intervals become larger up to 1000 km (new dpf with no ash)because the regeneration condition is not favourable
if highwayspeeds are reached between 500 and 1000 km the regeneration interval is shorter because of the favourable condition (less after injection because of higher engine baseload)
Its not only the interval wich counts but also the regeneration duration
Normally if my interval is shorter also the regenaration duration is shorter
The regeneration not restarting after a short interval hints at a favourable condition
If the regeneration had started at a high interval then always the regeneration will be initiated the first drive after highway or not

Check next time if the regeneration is started after a short interval if it was initiated at 55 miles/hour or faster and the duration of the regeneration
If the regeneration duration is shorter after a long interval where no speeds above of 55 miles/hour where reached everything will be function ok

If the dpf mileage becomes high with more ash in it those 500 and 1000km distances become shorter

Most times when regeneration starts it's been doing 55mph or more for at least a couple of miles. I didn't get to do that on my old commute but now I get two stretches on my 21 mile journey where that happens.

So could that be the answer? That it's checking every 200 miles or so, finding that conditions are favourable to regenerate nearly every time, and starting the process off? And on the old commute, it would more often find that it couldn't, and go back to sleep for another 200 miles?

I think the regenerations are also shorter now than they were. Seems like it takes 12-15 miles - maybe 20 minutes? I can remember some times last year that might even have been double that. Mostly the regenerations are completed every time now - it carries on even if I have to drive at less than 40mph for a while - I guess it would stop eventually but I'm not usually held up through villages for that long.

[5cilinder]

Originally Posted by Proghound

Most times when regeneration starts it's been doing 55mph or more for at least a couple of miles. I didn't get to do that on my old commute but now I get two stretches on my 21 mile journey where that happens.

So could that be the answer? That it's checking every 200 miles or so, finding that conditions are favourable to regenerate nearly every time, and starting the process off? And on the old commute, it would more often find that it couldn't, and go back to sleep for another 200 miles?

I think the regenerations are also shorter now than they were. Seems like it takes 12-15 miles - maybe 20 minutes? I can remember some times last year that might even have been double that. Mostly the regenerations are completed every time now - it carries on even if I have to drive at less than 40mph for a while - I guess it would stop eventually but I'm not usually held up through villages for that long.

If you dont do highwayspeeds the regeneration is suspended until its aprox 1000km and then its forced highway or not wich is long interval long regeneration
If after 500 km highwayspeeds are reached than regeneration is started because of the favoureble condition (higher engine baseload less after injection)
and because of the less soot accumulated thusfar the regeneration time shorter with the shorter interval
Those distances will be slowly reduced with ashaccumulation along the years
Regeneration is measured in time not distance ,if you drive very fast the enginebaseload is higher with more heat but the afterinjection is toned down to keep a steady temperature

[Proghound]

Originally Posted by 5cilinder

If you dont do highwayspeeds the regeneration is suspended until its aprox 1000km and then its forced highway or not wich is long interval long regeneration
If after 500 km highwayspeeds are reached than regeneration is started because of the favoureble condition (higher engine baseload less after injection)

That's sounds very like what I've been experiencing, except that the distances are more like 300km and 600km for me.

So if I understand you correctly, after whatever distance interval when it first becomes eligible for regeneration, there must be a range (perhaps 80km?) where it's looking for highway conditions in order to start regeneration. If it doesn't get them during that range, it waits for that distance interval again before forcing regeneration.

I know there's a pressure sensor in the DPF as well to measure soot buildup. Does that have any control over when it starts a regeneration (i.e. at some minimum level of buildup once the first distance interval is reached)? Or is the sensor only there to tell the system when the soot has all gone so it can stop regenerating?

[5cilinder]

Originally Posted by Proghound

That's sounds very like what I've been experiencing, except that the distances are more like 300km and 600km for me.

So if I understand you correctly, after whatever distance interval when it first becomes eligible for regeneration, there must be a range (perhaps 80km?) where it's looking for highway conditions in order to start regeneration. If it doesn't get them during that range, it waits for that distance interval again before forcing regeneration.

I know there's a pressure sensor in the DPF as well to measure soot buildup. Does that have any control over when it starts a regeneration (i.e. at some minimum level of buildup once the first distance interval is reached)? Or is the sensor only there to tell the system when the soot has all gone so it can stop regenerating?

The 500km/1000 km distances are theoretical with a new dpf with no ash
During the years that upper limit will shrink due to ash accumulation wich replaces soot accumulation space

The minimum distance (theoretical)is 500 km but driving conditions/ soot produktion are also limiting factors
In your case the minimum interval is aprox 300 km and is calculated with the distance travelled ,ash sofar accumulated (computerguess lineair with distance) pressure difference across dpf (sootaccumulation +ash) and fuelamount consumed and some educated gues of passive regeneration if the catalyst is above 400 celsius (high load driving)

The pressure sensor is used to determin if the soot is burned (lower pressure difference) but with callibration of the ash accumulation to factor in lasting pressure difference due to unburnable ash

Dpf 's are not required to replace despite waht the stealers are claiming ,dpf's can be vibrated en compressed air contra direction emptied of ash after the soot is burned because soot blocks of the channels wich all truck dpf's standard do in special automated machines , but can be done with your own dpf with common sense diy

[skyship007]

Originally Posted by Proghound

I have the D5 180 in my 2008 C70. It had 20k on when I got it 17 months ago but I've averaged about 1k per month, so it's now done 37k and just about fully loosened up.

Last year was I commuting 8 miles each way to the next town and back, in light to medium traffic. I also did regular longer runs of 15-50 fairly gentle miles at 45-65mph. I used to get DPF regeneration about every 400-450 miles. If one didn't complete, it would restart the next time the engine got warm enough.

Now I'm commuting 21 miles each way, mostly A-B roads, small towns/villages every few miles but basically always moving. I still do the same other regular runs also. So I almost never do any journey shorter than 15 miles - ideal conditions for the DPF you'd think.

What I find strange is that I'm now getting regenerations more often, at about 200-220 miles. But if they start too close to my destination to complete, they often don't restart, if the engine gets to cool down fully before its next use. Then it will do 180-200 miles to the next regeneration. I also had a 180 mile interval after a completed regeneration, which included 120 motorway miles at 65mph, but also 45 minutes of M25 crawl.

According to the manual, it's within tolerances - every 300-900km or roughly 185-560 miles - but only just. No messages about the soot filter have ever come up. I was wondering, might the DPF be hiding an increase in smoke output? Or is the system simply working as programmed?

I have already thought to run a bottle of injector cleaner through, adding it to a low fuel level and having a blast down the motorway for 20 miles while it was concentrated, before filling up. I now see about a 5% increase in economy (over 50mpg measured brim to brim), but no difference to the regeneration interval.

Any thoughts/comments, gentlemen?

How much oil are you burning and which type of oil are you using ??

Is the thermostat functioning correctly during warm up ??

Any fault codes stored ??

It does sound like the DPF is starting to get full and one simple test would be a good Sunday morning motorway session. If the Regen interval returns to a more normal figure, it is just a dirty DPF, if it gets worse, it's engine trouble etc.

One disadvantage with diesels is that 70 mph is not really good enough to cook up the exhaust enough to get it clean quickly.

PS: I only read this type of post so I can feel good about owning a pre DPF diesel!

PPS: I hope you are not doing this crazy 30K km OCI listed by Liqui Moly:

Engine D5244T4 ??
Use : Normal
· Intervals : Change 30000 km / 12 months
· Products : Leichtlauf Special V 0W-30
: Synthoil Longtime 0W-30


The Synthoil 0/30 is a great oil for the first 100K plus (Until the oil consumption creeps up), but short tripping or idling with a DPF is real bad news, so 15K km would be a more sensible oil change figure (Change the oil filter at 30K km). Once the oil consumption rises I would move up to an 0 or 5/40 and think about using LM Ceratec to try and cut the oil consumption and wear rates. You can't use HM (High mileage) oils in a DPF diesel, but Ceratec does help slightly with oil consumption and is real good at cutting bearing wear rates.

[Proghound]

Originally Posted by skyship007

How much oil are you burning and which type of oil are you using ??

Is the thermostat functioning correctly during warm up ??

Any fault codes stored ??

It does sound like the DPF is starting to get full and one simple test would be a good Sunday morning motorway session. If the Regen interval returns to a more normal figure, it is just a dirty DPF, if it gets worse, it's engine trouble etc.

One disadvantage with diesels is that 70 mph is not really good enough to cook up the exhaust enough to get it clean quickly.

PS: I only read this type of post so I can feel good about owning a pre DPF diesel!

PPS: I hope you are not doing this crazy 30K km OCI listed by Liqui Moly:
Engine D5244T4
Use : Normal
· Intervals : Change 30000 km / 12 months
· Products : Leichtlauf Special V 0W-30
: Synthoil Longtime 0W-30


The Synthoil 0/30 is a great oil for the first 100K plus (Until the oil consumption creeps up), but short tripping or idling with a DPF is real bad news, so 10K miles would be a more sensible figure.

The oil is Castrol Edge 0W30 A5/B5 Volvo spec. So far I'm 7k miles into it. I probably will change it again at 10-12k as I'm not sure I agree with an 18k mile interval either, even though I am doing nearly all longer journeys. I am using no oil that I know of - unless the regenerations are raising the oil level by the same amount! I don't know if any fault codes are stored but I don't have the Information light or any messages showing. The thermostat is fine, at the moment it's getting fully warm in 3-4 miles, in the winter it's more like 5-6 miles.

When I added the injector cleaner it was just after a regeneration had completed. I then took it straight out and did 80-90mph in 4th for about 20 miles - that's 3.5-4k revs, including plenty of hard accelerations from 3-4k. That was mainly to make sure that the injector cleaner had a good chance to work, but if it created a higher exhaust temperature to aid passive regeneration, so much the better. However that will also have produced a lot more soot for the DPF to catch. The next regeneration started about 220 miles after the last one completed, the same as usual.