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2017 Forester 2.0D CVT
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Thanks kutavayz,

that's rather reassuring. It was exactly that type of slow-speed city driving (that is not good for regens) that you described.

Also I wouldn't worry too much about your English. Just a couple of prepositions and/or pronoun issues here and there. Even Word's grammar checker didn't pick them up.

To digress, if all Aussies had English as good as yours our standard would improve considerably. I must say the standard on Subaruforester.org is quite high... I can think of a couple of other brand forums I've been on where you wonder if the monkeys have been playing with the typewriter. I'll suggest Subaru attracts a better class of buyer!
Hi!

Hahaha, thank you so much, I really appreciate your words :)

Talking about the blue smoke and oil smell. Do you have any wonders about it?
I don't understand why oil is in the equation of active regens.
I must say too that I never have any oil consumption. I always used Motul Eco-Clean 0W30. My Forester has now 93.000km since 16' February's and a 46% of DPF ash.

About the DPF additive cleaners I think about it many times, but I'm kind of worried because the owner's manual says that you must not add any fuel additives


Thanks again!
 

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2010 Forester Diesel 6MT
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809 Posts
Discussion Starter #282
Hahaha, thank you so much, I really appreciate your words :)
No worries! :smile:

Talking about the blue smoke and oil smell. Do you have any wonders about it?
I don't understand why oil is in the equation of active regens.
Yes I do wonder about the oil and for the exact same reason. It shouldn't be there. A few questions are: Is oil getting in all the time, or only during regens? Is it only evident during regens due to the higher temps? How and when and where is it getting in?

As I was only behind the car during a regen I can't say whether there is similar smoke/smell during 'normal' running. But I'm sure if there was then when the car was parked both my wife and daughter would have noticed and asked me about it.

I'll assume the oily smoke it's only seen/smelt during the regens and perhaps only early on at that as it clears out. The oil-in-the-exhaust sources I can think of are:
a) valve guides
b) piston rings
c) emission control systems- oil/sump breather, EGR (somehow)
d) turbo bearing leaks
e) overfilled, overdiluted or overpressurised oil

So let me make some hand-wavy opinions:
a) and b) - if the piston oil rings or valve guides were at fault we'd have smoke during normal driving the same way a 'normal' worn engine would
c) If the PCV valve is stuck and/or there's excessive blow-by (compression rings, wear) and/or the oil is poor (dilution) this could introduce extra oil to the intake which could filter through to the exhaust, burn when it regens.
d) Exhaust-side: this will introduce oil directly to the exhaust. Intake side: could possibly lead to a diesel runaway. Either way it's not good.
e) Over filled oil- could be caused by overdiluted oil, which is also aspirated more easily (see c above) and therefore ingested through the intake system. Otherwise straight overfill can lead to excess oil splash/aspiration anyway , perhpas over pressure and therefore intake ingestion.

Again, all speculation- you'd need to see/check the oil, intake manifold, exhaust, turbo, PCV/oil breather just to check.

About the DPF additive cleaners I think about it many times, but I'm kind of worried because the owner's manual says that you must not add any fuel additives
I agree entirely and that's why I've waited so long to use one. Now we're at a possible DPF reclean/replacement issue (again) anyway. Also the companies have had time to bring their additives up to speed for DPFs. The Penrite brand is an Australian company that designs products specifically for the Australian market & vehicles. I'll put the link to the product below, but they actually state it is specifically for DPF-equipped vehicles and is not recommended for non-DPF-equipped ones.

The product is Penrite Enviro+ DPF Cleaner - scroll down to the text.
 

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2017 Forester 2.0D CVT
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Thank you so much for your complete reply.

Tomorrow I will take the car to the dealer because last night I observed some engine oil drops on my garage soot and I saw a leak in the zone of the front diff, but it came from the upper zone of the engine, I can't see where.
I don't know if this could be related to the oil smell and blue smoke problem... My car drops bluish smoke from the very first day since new, but until the other day I never smell any oil, only burnt smell typical of the DPF regens in every car.
Now I'm pretty worried because with 35.000km dealer changed all the timing chain system due to a defective part. I don't know if this could be related...
I let you some photos of the leak zone. I'm sure is engine oil because of the color and viscosity.

 

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2010 Forester Diesel 6MT
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809 Posts
Discussion Starter #284
Kutavyz,

you should find out where'that's coming from. From the buildup it looks like it has been happening for some time.

Also that oil, if it's getting on to the hot exhaust esp during a regen, could be the cause of the oily/burnt oil smell. And also a fire hazard!
 

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2017 Forester 2.0D CVT
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Hi again!

My dealer told me that they can't find any oil leak and that the oil dropping comes from a spill during a service... They cleaned it one month ago and until now no oil dropping. Thanks you so much, pitrack_1 for your interest and your replies.

And now, talking about the DPF, I'm very tired of the continuous DPF regenerations. It's well known that in summer DPF regens becomes stupid. Regen intervals drops and the soot amount varies a lot, increasing the soot reading when coasting. Nobody knows why.
The thing is that this summer regens stay stable (250/300 km), but from two or three weeks ago I'm doing regens every 100/130 km. Soot reading become crazy, for example, reading 40% when the car is cold, dropping to 10% at the middle of the trip and raising up at the end, specially when coasting to 55 or 60%.
This week the soot level remains more stable, talking about soot level difference between the start of the trip and the finish. But today, after 190 km since last regen and arriving home with a 48% of soot (43% when the trip started) I let off the gas to take the exit of the motorway and soot start raising and DPF regen starts with 68% of soot. My day to day trips takes about 23 kilometers in the morning and another 23 in the evening, almost the total of the trip in the motorway @~100 kmph.
I can't undertand nothing about this behavior... Nothing changed in the last days, same fuel, same service station, same driving conditions, no oil consumption at all... I don't know if this could be related with the occasional blue smoke during regens, but it does it from the very beggining...
My car has 97.000km now and is an Euro6 model.


Any thoughts?


Thank you so much :)
 

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2014 Forester 6 M/T
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46 Posts
I have similar experience with crazy DPF regens at summer time. I have EURO V and at my last road trip this summer I had quite serious issue with short distances between DPF regens. I found possible issue, loose intercooler pipe. I tightened those metal rings on both ends. See attached picture. Especially upper ring almost dropped down and bottom of the pipe was dirty and oily. Worth checking, because older models before EURO V, has issue with breaking of the pipe and the symptoms was excessive DPF regens. 20180917_093745.jpeg 20180917_093917.jpeg

Sent from my SM-G930F using Tapatalk
 

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Hi!

One of the first things I checked was the intercooler pipe, looking for cracks or any damages. My pipe is fine apparently, but I've not checked out if the connections are tight enough, I'll check it tomorrow.
Do you solve the problem with this tip?

Thanks a lot!
 

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Hi, hard to say if tightening helped, because now it is quite cold outside and I have almost 2000km from last active regeneration. I have to wait until next spring/summer to see if tightening made any difference. But at the end of the august and begining of septer, when I was at summer vacation/road trip, I have serious issue with DPF regens happend every 50-120km even on highways. This drop happened quite rapidly after 500km. Oil dilution increasing rapidly too. It was looking that I will have a problem to return home, but after tightening pipe ends at the campground the distance between DPF regens starts increasing, so I happily returned home with my family. I got a feeling that now it is a way better and it looks like any leak at air intake after turbocharger can cause troubles with DPF. I let my service dealer to check the whole path, just to be sure. Actually I have 100,000 km and ash at 41%. If DPF will become crazy at spring/summer again I plan to send it for cleaning at special professional service.
 

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2010 Forester Diesel 6MT
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809 Posts
Discussion Starter #290
Hey pitrack_1. I've just started a group on Facebook for Subaru diesel owners in Australia. We'd be glad to have your knowledge in the group - if you're on Facebook, of course.
Hi notnothing,

Sorry for the late reply- I don't log on all that often. Thanks for the info, I think that's a great idea to start your group. However I'm not a member of the book of farce, but I wish you all the best.
 

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2010 Forester Diesel 6MT
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Discussion Starter #291
Hi kutavyz and svkforester,

Hi again!

My dealer told me that they can't find any oil leak and that the oil dropping comes from a spill during a service... They cleaned it one month ago and until now no oil dropping. Thanks you so much, pitrack_1 for your interest and your replies.
wow, that's about the best solution possible- no leak, just a spill AND an admission from the dealer!

...I let off the gas to take the exit of the motorway and soot start raising and DPF regen starts with 68% of soot.
I experienced the exact same thing- exit ramp off the freeway (90km/h) coast to a stop triggering a regen. Your driving and sott level experience is very similar to mine. I cannot account for it, i can only suggest some miscalibration or other issue with the DPF pressure sensing, or something loose (e.g. part of the filter material) in the DPF, or ??? . Perhaps a recalibration of the DPF system may be necessary. Perhaps also the pressure sensors and/or pipes to them have become partially blocked. I'm assuming (because I haven't seen) that there are pressure sensors before and oafter the DPF and the differential between these is used to estimate the soot level. If so, and the upstrem one became almost fully blocked (reasonable given that's where the soot/oily stuff most likely is), under coasting the pressure may reduce in the downstream one, but remain due to the blockage in the upstream, causing the increase in soot reading and regen initiation. You may need to demonstrate this to the dealer, i.e. the coasting increase in soot level whilst the dealer has their scan tool plugged in so they can see the parameters, they may be able to make a determination from that.

Our car was helped recently by a DPF cleaner additive, this may be worth a go (when out of warranty).

Also it sounds like both of you have been having similar issues to what I had with the pipes and/or joints and/or other leaks seem to cause issues, but I believe also the summer diesel may be contributory on the earlier model (~2010) EURO5 due to a different blend. Otherwise maybe the weather also "opens up" or exacerbates any leaks/cracks.


Good luck!
 

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2017 Forester 2.0D CVT
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Hi, hard to say if tightening helped, because now it is quite cold outside and I have almost 2000km from last active regeneration. I have to wait until next spring/summer to see if tightening made any difference. But at the end of the august and begining of septer, when I was at summer vacation/road trip, I have serious issue with DPF regens happend every 50-120km even on highways. This drop happened quite rapidly after 500km. Oil dilution increasing rapidly too. It was looking that I will have a problem to return home, but after tightening pipe ends at the campground the distance between DPF regens starts increasing, so I happily returned home with my family. I got a feeling that now it is a way better and it looks like any leak at air intake after turbocharger can cause troubles with DPF. I let my service dealer to check the whole path, just to be sure. Actually I have 100,000 km and ash at 41%. If DPF will become crazy at spring/summer again I plan to send it for cleaning at special professional service.
Hi!

I checked again the intercooler pipe and apparently there's no oil in the joints, I can't see any cracks neither.
I tighten one of the screws but it was tight already. The other screw is under the intercooler and I can't reach it.
I don't know where the turbo pipes are.



Thanks!
Hi kutavyz and svkforester,



wow, that's about the best solution possible- no leak, just a spill AND an admission from the dealer!

I experienced the exact same thing- exit ramp off the freeway (90km/h) coast to a stop triggering a regen. Your driving and sott level experience is very similar to mine. I cannot account for it, i can only suggest some miscalibration or other issue with the DPF pressure sensing, or something loose (e.g. part of the filter material) in the DPF, or ??? . Perhaps a recalibration of the DPF system may be necessary. Perhaps also the pressure sensors and/or pipes to them have become partially blocked. I'm assuming (because I haven't seen) that there are pressure sensors before and oafter the DPF and the differential between these is used to estimate the soot level. If so, and the upstrem one became almost fully blocked (reasonable given that's where the soot/oily stuff most likely is), under coasting the pressure may reduce in the downstream one, but remain due to the blockage in the upstream, causing the increase in soot reading and regen initiation. You may need to demonstrate this to the dealer, i.e. the coasting increase in soot level whilst the dealer has their scan tool plugged in so they can see the parameters, they may be able to make a determination from that.

Our car was helped recently by a DPF cleaner additive, this may be worth a go (when out of warranty).

Also it sounds like both of you have been having similar issues to what I had with the pipes and/or joints and/or other leaks seem to cause issues, but I believe also the summer diesel may be contributory on the earlier model (~2010) EURO5 due to a different blend. Otherwise maybe the weather also "opens up" or exacerbates any leaks/cracks.


Good luck!
Hi again, Pitrack.

I'll keep an eye in the possible oil leak. Dealer told me about the spill but I'm not so sure. At least the oily area remains clean. So if there's a leak, it must be very small. No oil consumption neither.

Your coasting regens theory makes sense, the problem is how to involve the dealer in it. I will take my car to it before my warranty expires (I have 98k) and see what happens, I'll keep you informed.

The curious thing is that the crazy soot reading only happens in my day to day trips (44 km in two trips of 22 each by the motorway @~100km/h and from cold starts). For example, last weekend I did a trip of 550km with no regens and coasting affected nothing at all, soot remained stable.
Like you said, there's two pressure sensors in the DPF inlet and outlet. I have the pressure difference PID code in Torque to see if there's some kind of trouble but I can't reach any conclusion. When coasting pressure difference usually stays at 2 kPa and at engine load it's variable. I can't link the pressure difference value with the soot value.
One other thing that I observed is that this cars usually runs very cold for a long time, and I thing this is one of the best things to increase soot levels.
My car at my day to day trips takes at least 14km to reach 90 °C.



Thank you so much for your help and your time. I hope I've explained myself.
 

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2010 Forester Diesel 6MT
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Discussion Starter #293
Hi kutavyz,

Thanks for the reply and your info, you've explained yourself very well!

Your driving was extremely similar to mine for the same issue- about 20km each-way home to work, in combined city/[email protected]/h driving. And my temp was also quite slow- it would often take between 3.5 to 5.5km for the blue light to go off (50C) and the heater to even passably be warm. It would take approx 15km to get to 90C I think.

I think part of the problem is diesels are so efficient they don't generate as much waste heat. I'll also assume the greater engine block weight from the required structural strength compared to a petrol engine also means more mass to heat, probably thicker walls and therefore a slower temp rise.

Someone else in Australia who has had similar issues and has found some cleaning solutions just posted in the past few days, you can read from this post on. It will make interesting reading for you, in particular regarding cleaning the engine and also dealer liaison.
 

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2017 Forester 2.0D CVT
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Hi kutavyz,

Thanks for the reply and your info, you've explained yourself very well!

Your driving was extremely similar to mine for the same issue- about 20km each-way home to work, in combined city/[email protected]/h driving. And my temp was also quite slow- it would often take between 3.5 to 5.5km for the blue light to go off (50C) and the heater to even passably be warm. It would take approx 15km to get to 90C I think.

I think part of the problem is diesels are so efficient they don't generate as much waste heat. I'll also assume the greater engine block weight from the required structural strength compared to a petrol engine also means more mass to heat, probably thicker walls and therefore a slower temp rise.

Someone else in Australia who has had similar issues and has found some cleaning solutions just posted in the past few days, you can read from this post on. It will make interesting reading for you, in particular regarding cleaning the engine and also dealer liaison.

Hi Pitrack!

Thank you for your help :)

I'm calmer now about the coolant temperature now. I'm still thinking that it's too much time to the engine be warm up because it's obvious that a cooler temperature produces more soot, engine and DPF wear...
And I agree with you too with the probable reasons...

Now, talking again about the strange DPF regens, I think that I found the reason of them.
The strange behavior of the regens started with an automatic injector learning/calibration ~3000 km ago. When I saw it I thought that it was only a coincidence, but two days ago and after another 3000 km the car did an injector learning. After that day the soot level it's completely stable and it only rises with the time. I think the regen intervals have improved, not much but at least it's something. Now I'm @ 57% soot and probably tomorrow evening the DPF regen will trigger. I will be observing if this behavior is maintained.
I can't relate the injector learning with the erratic soot readings. I could understand that if the calibration is not perfectly done the engine produces more soot, but I can understand why this could be related with the ups and downs of the soot readings.
Here you have an article of the injector learning process:

https://subdiesel.wordpress.com/2011/02/15/injector-learning-calibration/

Thanks for sharing with me the post in OzFoz. I'll keep an eye in it for sure.
 

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2017 Forester 2.0D CVT
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96 Posts
Hi!

I leave you a video of the Torque app from the start of my home to job route (≈21 km from cold start). I still don't know what is causing this behavior.

 

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2010 Forester Diesel 6MT
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809 Posts
Discussion Starter #296 (Edited)
Hi kutavyz,

hmmm, never seen it like that, well done. Not plotted up the Pressure diff previously- something I obviously should have done.

If you observe the video you will note that the Soot (Hollin(?) I assume Spanish? Sorry but using Google translate, I'm language-illiterate) increases after a delay from an increased pressure differential. I assume the increased pressure differential is from an increase in throttle/speed/fuel input going by the DPF temp.

So I'm going to assume the soot is calculated relating to some algorithm that related soot level to pressure vs time, with a delayed response- some sort of integral under the curve over the previous x no of seconds, perhaps with some floor level increasing over time (bit like the oil dilution). No doubt other parameters also play into this, such as exhaust/DPF temp, engine load, Mass Air Flow, etc. Note: this is just a technician's speculation/(un)educated guess.

I think the pressure differential may be a bit high though getting to 12kPa. If so that would explain why the soot scales quickly (I realise the video is sped up). What is causing that I don't know- miscalibrated sonsors, blocked/partially blocked sensors, partially blocked DPF, etc. See this link as an example, esp. the quote:
Engine manufacturers are usually much more conservative on their back pressure limits. For example, diesel generator set engines from Caterpillar, Cummins, John Deere and DDC/MTU ranging in size from 15 to over 1000 kW have back pressure limits ranging from 6.7 to 10.2 kPa.
That's why at a ~12kPa back pressure reading the car's rapidly scaling to start a regen.

DPF temp may be a tad low most of the time also but that may be a function of ambient which I guess is close to 12C (intake's always usually a few degrees above that).

It might be good to log the accelerator pedal position, revs and speed during this as well to get a better idea of what conditions prompt the rapid increase in soot.

(Ahem) Another post shortly I think I've found an explanation for something that's been bugging us for a while...
 

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Discussion Starter #297
DPF Soot level scaling pattern explained...perhaps!

Now I think most of us have noticed, in a steady state situation, the soot after a regen rapid climbs to ~40 % the slowly climbs thereafter through the 40's and 50's. Well, I think I've found a page that explains this.

The page is "Basics of Diesel Particulate Filter (DPF) Operation" from CTS.

To summarise the page:
- DPFs trap soot in two ways: in the pores and on the surface of the channels.
- Pores fill up quickly and the pressure differential rises quickly along with it. (I'd suggest that's the rather rapid rise to 40%)
- Soot then builds along the channels walls which, being much larger can hold a lot more soot and thus the pressure differential rises much more slowly and for much longer (I'd suggest 40% up).

A few salient quotes from the page:
Soot particles are captured and retained in the DPF through a combination of depth filtration inside the filter pores and surface filtration along the channel walls. The inset in Figure 1(c) shows these two processes, where a small fraction of the soot initially accumulates in the filter pores (1) and then subsequently builds a layer along the channel walls (2). As the soot load in the filter increases, so too does the filter’s trapping efficiency, as the accumulated soot provides an additional layer to trap incoming particles. The specific soot filtration mechanisms, whether in the pores on the surface of the walls, plays an important role in determining the overall increase in exhaust back pressure (or pressure drop across the filter), shown in Figure 2.
(Figure 2)
... In a new or clean DPF, the surface of the filter is exposed to the exhaust flow and soot rapidly accumulates in the surface pores. Although only a small fraction of the total soot accumulates in the filter micro-pores, it contributes to a steep rise in filter pressure drop shown in Figure 2. Subsequent soot accumulation in the DPF forms a layer (cake layer) along the walls of the channel, and results in a slower and more gradual rise in filter pressure drop [3]. Depending on the soot loading level and filter type, the pore accumulation can account for 50% of the filter pressure drop, or more, in some cases. The non-linear response of the DPF to material accumulation complicates the determination of filter soot or ash loading levels based on pressure drop alone
 

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2017 Forester 2.0D CVT
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Hi Pitack_1,

Thank you so much for your post, as always, they're very helpful.
In a few minutes I'll coming home and I will try to record the trip back home with the revs, speed and accelerator pedal angle.
About the DPF temperature, it's the same most of the time, even in summer with +35 degrees celsius temperatures.
About the language, don't worry. "Hollín" is soot and "Ceniza" is Ash cumulative ratio.


Thanks again :)
 

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2010 Forester Diesel 6MT
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Discussion Starter #299
Kutavyz,

no worries! (That's Australian for "that's OK").

Done a bit more reading and coming to the opinion that your suggested ash cleanout of the DPF may be a very good idea. If your DPF is highly ash loaded that would explain the short regen cycles and perhaps also the high backpressure esp. under load.

Certainly won't hurt.
 

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Hi again,

I let you the go back home video. This time with a full DPF regeneration process. Of course, DPF regen starts at 4 minutes of home and I need to take a go around to complete de regeneration process.
Maybe the video is too speeded up, but if you want the original I could upload it.
The accelerator angle PID does not work well, probably because a bad formula, but is useful to see when I'm not accelerating (0.0%) To make an idea, in my trips the Accelerator angle in the MFD never shows more than 30%. In this trip it was between 6/17%.
Exterior temperature 18 ºC, speed 2 km/h more than showed.





Thanks!
 
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