# Filthy Air Filter and DPF issues.



## oregon_rider (Jul 21, 2017)

I have recently had issues with dpf plugged - engine power reduced and check engine light, etc. It went to the dealer and had a "service regen" performed in the parking lot. And it ran fine for another week and a half and set a code again...

The vehicle has 18k miles and, yes, it is occasionally driven on short trips - my daughter has it at college. So it isn't surprising we might have an issue with the DPF. But there had been no problems up to this point and she was actually taking more freeway trips than she had in the past.

I asked them to check the air filter - and they said they did and it was fine. They didn't and it wasn't... 

I decided to replace it anyway and it was obvious that it hadn't been checked and was filthy/plugged. 

My guess is that the DPF regen was being hampered because the engine was not running efficiently due to the plugged air filter.

The service interval for the air filter is 45k miles/4 years. After seeing what it looked like after 2 years and 18k miles, I am going to an annual replacement for the air filter. 

Just a heads up to everyone here that you may want to ignore the owners manual for air filter service interval and replace it annually. I bought an ac delco filter through amazon for $25.

jeff


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## Roger Ramjet (Oct 11, 2018)

Did the air filter replacement resolve the issue? Is it Gen 1 or 2?


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> I have recently had issues with dpf plugged - engine power reduced and check engine light, etc. It went to the dealer and had a "service regen" performed in the parking lot. And it ran fine for another week and a half and set a code again...
> 
> The vehicle has 18k miles and, yes, it is occasionally driven on short trips - my daughter has it at college. So it isn't surprising we might have an issue with the DPF. But there had been no problems up to this point and she was actually taking more freeway trips than she had in the past.
> 
> ...


I wondered if my issues with regens had been due to this but I don't think my air filter looks too bad. Maybe I should check again. Not sure if this is standard to all of them, but mine has a sort of weird outer sleeve that makes it hard to see the filter itself, but I didn't want to peel it off.


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## oregon_rider (Jul 21, 2017)

Roger Ramjet said:


> Did the air filter replacement resolve the issue? Is it Gen 1 or 2?


It hasn't happened again - but not enough time has transpired to draw any conclusions.

this is the gen 2 diesel sub-forum - and yes, it is a gen 2 - a 2017 diesel cruze sedan with Auto transmission

jeff


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## Barry Allen (Apr 18, 2018)

BodhiBenz1987 said:


> mine has a sort of weird outer sleeve that makes it hard to see the filter itself


I read somewhere that is a snow screen. Go ahead and take it off when you install the new air filter. It isn't catching much anyway.


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## oregon_rider (Jul 21, 2017)

Barry Allen said:


> I read somewhere that is a snow screen. Go ahead and take it off when you install the new air filter. It isn't catching much anyway.


 yes. it is for snow - at least my old vw golf had same thing and this is what it was said to be for....

I would leave the white coarse foam on - it makes a nice pre-filter... It was holding a bunch of stuff on mine - it looked quite dirty so it was doing something - it is fairly coarse so it isn't restrictive and can only "do good"....

jeff


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## HondaTech2016 (Apr 20, 2017)

I did my first air filter at 25k miles and it wasnt horrible, I do them every 30k now and the 2nd 1 wasnt that bad either at 55k. I also do cabin and fuel filters at the same time. 

My first 15k miles or so were mostly short with the occasional long trip and never had any issues. I've since taken a job over an hour away and still haven't had any problems.


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## oregon_rider (Jul 21, 2017)

Well it happened again. Third time the code has been set on about 3 weeks of driving.

Second trip to dealer on issue happens tomorrow.....


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## //oilburner (Mar 9, 2019)

Those coarse screens actually serve a purpose - to catch aspirated stuff in the air. The worst airborne items besides dust is salt water from Winter road grime and living near the coast. You do not want salt building up in the air box (because the next stop is the engine). There may be on some car designs a post-engine air filter screen - do not remove that as well. It serves as a laminar flow element so that air speed inside the plenum meets the requirements for those downstream sensors like the MAF and delta-P sensors.


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## oregon_rider (Jul 21, 2017)

Update on new visit to dealer - they did another service regen. The day before service visit, I took it out on road and did a very long "italian tune up" - high rpm running to try to clear dpf and cat, etc. On trip to dealer the next day, it regen'ed quickly and down to 2% according to tech. When I got in car after the service - the soot load read 0% on my scangauge 2.

The tech thinks that the catalytic converter might also be plugged up from all the short trips over the last year - hopefully - the italian tune up helped clear it out. But talking to a friend of mine who is an ASE master tech - it might help "a little bit" - but it will take a long time to clear it out... Time will tell - will update this post again in a few weeks...

jeff

p.s. I like the info the scangauge 2 gives me. You are kind of blind without it. Difficult to program in "xgauges". Right now, I am showing soot %, regen status, and number of miles since last regen. Regen status doesn't show anything right now - I might have it programmed in wrong...


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## oregon_rider (Jul 21, 2017)

I have been looking at additives that are sold in europe for keeping the dpf clean.

There are several available and they employ cerium oxide. This lowers the temp at which the soot will burn. So the regeneration becomes more effective - it burns off at a much lower temperature with the additive.

One that seems more available here in the u.s. is made by liqui-moly....









_*Diesel Particulate Filter Protector*_ - I ordered two cans off of ebay to give it a try...

jeff


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## HondaTech2016 (Apr 20, 2017)

oregon_rider said:


> I have been looking at additives that are sold in europe for keeping the dpf clean.
> 
> There are several available and they employ cesium oxide. What it does is lower the temp at which the soot will burn. So the regeneration becomes more effective - it burns off at a much lower temperature with the additive.
> 
> ...


Pretty sure they say not to use that product on vehicles equipped with an electronic additive tank for filter regeneration (i.e DEF).
I know they reference the Peugeot and Citroen only, but if you look up either of those they use what they call EOLYS fluid which is just another name for AdBlue.

I'd be cautious on that stuff if that's the case.


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## oregon_rider (Jul 21, 2017)

HondaTech2016 said:


> Pretty sure they say not to use that product on vehicles equipped with an electronic additive tank for filter regeneration (i.e DEF).
> I know they reference the Peugeot and Citroen only, but if you look up either of those they use what they call EOLYS fluid which is just another name for AdBlue.
> 
> I'd be cautious on that stuff if that's the case.


 Thanks for bringing that up - I saw that and dug into it before making my decision and posting here.

You are correct in that the eolys additive (and automated injection system for it in peugeot/citroen) is to aid in diesel particulate filter regeneration. But you are incorrect in stating that is the same as AdBlue (DEF).


The additive that I mentioned uses the same active ingredient as eolys - it is a cerium oxide based additive that reduces temps that soot will ignite - which aids and speeds both passive and active dpf regeneration.

These DPF cleaner/protector additives all state that you should not overdose/ over-additize... If you were to add this additive to an older citroen - this would occur - you would get additive from injection system plus additive in fuel. 

There is no issue in using these types of additives in our cruze diesels as we don't have a catalyst injection system to help with DPF performance/behavior. We have a urea injection system (DEF) for reducing NOx emissions.... Different animal....


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## Barry Allen (Apr 18, 2018)

oregon_rider said:


> I have been looking at additives that are sold in europe for keeping the dpf clean.


You might do better/cheaper by using a cetane boosting additive with every tank of fuel. Having diesel fuel with high/higher cetane means combustion starts easier and burns more completely. We have terrible diesel fuel in a lot of the USA because there is no real federal standards for motor fuels that we desperately need. Gasoline needs to be brought up to 89 octane as the new "Regular" grade so we can have better turbocharged engines, and diesel fuel needs to be brought up to higher cetane levels like is done in California and Texas. Everything I've read (and it's not an exhaustive search) is that a cetane improver helps keep the DPF clean from the start because if you can avoid generating the soot at the start by having cleaner combustion, that's less soot that lands in the filter and has to be cleaned out with a regen cycle.


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## oregon_rider (Jul 21, 2017)

Barry Allen said:


> You might do better/cheaper by using a cetane boosting additive with every tank of fuel. Having diesel fuel with high/higher cetane means combustion starts easier and burns more completely. We have terrible diesel fuel in a lot of the USA because there is no real federal standards for motor fuels that we desperately need. Gasoline needs to be brought up to 89 octane as the new "Regular" grade so we can have better turbocharged engines, and diesel fuel needs to be brought up to higher cetane levels like is done in California and Texas. Everything I've read (and it's not an exhaustive search) is that a cetane improver helps keep the DPF clean from the start because if you can avoid generating the soot at the start by having cleaner combustion, that's less soot that lands in the filter and has to be cleaned out with a regen cycle.


 Thanks for that comment and it is definitely a good thing to consider....

To avoid fuel issues here on the west coast. I am fueling only with Chevron products. Only chevron diesel for the cruze diesel and chevron premium in our buick encore with 1.4T (LUV engine)

And here in oregon there is a mandate for 5% biodiesel (b5). Chevron imports soy biodiesel into the state for their blends due to it's higher stability. This cleans & lubricates injectors and hpfp (high pressure fuel pump).

In the past, I ran an additive religiously in my duramax. But more recently I use chevron diesel #2 (it has higher cetane) with b5 mandated (5% bio blend required in this state). For chevron it is 5% soy bio in the mix. Given this, I don't feel the need for an additive - the soy biodiesel in the mix provides for a squeaky clean set of injectors and hpfp and the cetane is nice and high... 

Given my daughter's use of the car - I am still thinking the dpf protector/cleaner additive is a good way to go to avoid issues in this case. As a side benefit, it will also keep the EGR clean...

jeff


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## oregon_rider (Jul 21, 2017)

Just thought I would drop a line here to give feedback on the dpf cleaner additive that I used. It is the liqui moly DPF protector that I mentioned previously in this thread.

My daughter had the car at college and came home for a few days. She had driven the car about 300 miles since I had put the DPF cleaning additive in the car.

I noted a couple of things....

1. The distance since last Regen was 250 miles and the soot load was a very respectable 42 percent. 

2. When pulling on to the highway and accelerating the car rev'ed much, much more quickly to higher RPMs. It was obvious to me the car was running much better and that the exhaust was previously quite obstructed.

I would recommend this product to anyone who is having DPF issues.

The tech at the dealership on a previous visit thought the cat was also plugged from driving short trips. I would imagine the egr was quite dirty as well.

The additive lowers the temp at which soot will ignite. This makes both passive and active Regen much more effective. Besides cleaning the DPF it should also help clear a cat plugged with soot. And will also help clean and help keep.the egr clear.

You can run this additive every 1200 miles driving. It is sold through Napa but not stocked in most stores. You can order on line at Napa website and have it delivered to your local Napa. It is also available on eBay or Amazon at a higher price...

Jeff


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## oregon_rider (Jul 21, 2017)

I just ordered some Diesel Particulate Filter Protector (made by liqui moly) from napa online - I had a hard time finding it this time around. To avoid someone else the hassle I just went through - here is a link to it in their on line store...



https://www.napaonline.com/en/search?text=%2BAIC%2BLM2000&referer=semantic&se=1












_"Highly-effective additive that reduces the build-up of particulates and therefore extends service life of the diesel particulate filters. Vehicles used for short trips and city traffic are especially affected by problems with clogged diesel particulate filters. Regular use keeps the diesel particulate filter clean, avoiding expensive repairs and down times. Diesel Particulate Filter Protection ensures optimum fuel combustion and reduces the build-up of particulates. This also contributes to reducing emissions. "_

On checkout - you can specify a 10% AAA discount - which made it a pretty good deal - about $8.50 a can... No shipping as I am picking up at a nearby NAPA store.

Good stuff...

jeff


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> Just thought I would drop a line here to give feedback on the dpf cleaner additive that I used. It is the liqui moly DPF protector that I mentioned previously in this thread.
> 
> My daughter had the car at college and came home for a few days. She had driven the car about 300 miles since I had put the DPF cleaning additive in the car.
> 
> ...


Hey Jeff, I'm wondering if you have continued to use the LiquiMoly additive and what your longterm thoughts are on it. I'm considering trying it in my car as I continue to have issues with erratic short regen cycles. I know these additives are really designed to help people who don't drive enough highway to get solid EGTs, which is not my case, so I'm not sure it will help. But if there isn't any risk associated it seems like a good thing to try. Even though I think my problem is electrical/ECM, if I can give the DPF a little leg-up on passive regen temp, I might be able to reduce the wear and tear. Which is at this point all I can do because I've tried and tried (and tried more) and no one can figure out the issue.


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## Cruz15 (Mar 17, 2016)

I have been using a cetane improver since new no regen problems here 2 years in


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## BodhiBenz1987 (Jan 13, 2018)

Cruz15 said:


> I have been using a cetane improver since new no regen problems here 2 years in


Which brand do you use? The LiquiMoly seems most available and has good reviews so I was going to try that one, but I'm open to any suggestions ... not super worried about price. I've never had a problem with regens completing (never had to have a service regen or anything), just that they are very frequent despite highway driving. For wear and tear purposes it would be great to spread them out a bit more especially if I go on a road trip (whenever we are allowed again).


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## Cruz15 (Mar 17, 2016)

Stanadyne Performance Formula Diesel Fuel Additive Blue bottle, certified by GM for use in GM diesel vehicles.


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## oregon_rider (Jul 21, 2017)

BodhiBenz1987 said:


> Hey Jeff, I'm wondering if you have continued to use the LiquiMoly additive and what your longterm thoughts are on it. I'm considering trying it in my car as I continue to have issues with erratic short regen cycles. I know these additives are really designed to help people who don't drive enough highway to get solid EGTs, which is not my case, so I'm not sure it will help. But if there isn't any risk associated it seems like a good thing to try. Even though I think my problem is electrical/ECM, if I can give the DPF a little leg-up on passive regen temp, I might be able to reduce the wear and tear. Which is at this point all I can do because I've tried and tried (and tried more) and no one can figure out the issue.


Hey There
Getting cat replaced seems to have resolved issue. 

I never used the liqui moly dpf protector that much. Still have a few bottles in the garage

I have found that running renewable diesel resolves any problems I might have

For example, I started out at 58 percent soot load yesterday morning. Ran a few errands around town yesterday afternoon and todaya andnever got over 35 mph. The soot load dropped to 40 percent. 

The dpf protector has ferrocene as it's active ingredient. I think it would be fine for occasional use. But for regular use would probably foul the cat and Nox sensors.

I think you need to give it some more time. It is probably an adaptive algorithm that needs some time to "learn". 

I think running a cetane improver will definitely help you and you can run it all the time. The liqui moly cetane improver cans are a nice size as they are made for euro car market with one dose being good for our 13-14 gallon tanks.

That being said, I have always like running stanadyne additives. Great for winter use

Jeff


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## BodhiBenz1987 (Jan 13, 2018)

@Cruz15 @oregon_rider Thanks for the input. I actually just tried the Stanadyne blue bottle on the last refill, only been a few miles so I will see how it does. I like the idea of running that regularly anyway, especially next winter. Unfortunately we don't have renewable diesel here, would love it if we did. I try to use top tier only but I'm never sure how much that means. I still lean towards thinking I am not making as much soot as it "thinks", but anything I can do to run a little cleaner and keep the injectors in good shape is a plus. I am still hoping it will finally learn the right values, I never quite understand how that works ... I'm decent with mechanics but when it comes to computers I am definitely, well, an English major.


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## //oilburner (Mar 9, 2019)

I haven't had any issues but my commute is 80 mi RT each day and I've been working through the SARS-CoV-2 outbreak. I typically have to "floor it" with a few on-off ramps and with my MT I also frequently wind it up. I wonder if that's keeping any regen issues at bay? I've been religious about using Shell Diesel, no fuel additives, and 5-7 K oil changes (Rotella T6, early on changing the oil every 1-3 K miles during break-in) that I do at home.


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## BodhiBenz1987 (Jan 13, 2018)

//oilburner said:


> I haven't had any issues but my commute is 80 mi RT each day and I've been working through the SARS-CoV-2 outbreak. I typically have to "floor it" with a few on-off ramps and with my MT I also frequently wind it up. I wonder if that's keeping any regen issues at bay? I've been religious about using Shell Diesel, no fuel additives, and 5-7 K oil changes (Rotella T6, early on changing the oil every 1-3 K miles during break-in) that I do at home.


Generally a lot of highway and driving a bit hard at times helps a lot ... even just normal highway the EGTs stay high enough to passively regenerate, plus when you do need an active regeneration it can complete easily and all the way. I think if you drive like that and use the right oil, you shouldn't need anything else. Mine is an exception to the rule so after a year of trying to get it fixed I was looking beyond to additive and desperate measures that are usually intended for people who can't get on the highway enough. When I was doing an 80-mile RT commute every day, mine was doing an active regeneration every other day and often back to back days (couple times more than one a day). That said, it has never failed to complete one or thrown any related codes, so the highway does help in that regard. In my case it's not that the DPF gets clogged or won't regen, it's just that it does it so much it will eventually be damaged prematurely because it's doing so many more regens than it needs to; under normal circumstances they stay healthy with regular highway usage. So I don't think someone like you needs to worry other than keep using the right oil.


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## Barry Allen (Apr 18, 2018)

//oilburner said:


> Rotella T6


Uh, that's not a Dexos 2 oil required by GM. Though, if you're out of warranty, no one cares.


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