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What can influence EGR cooler clogging?

Discussion in 'Prius v Technical Discussion' started by Ronald Doles, Jun 16, 2021.

  1. Ronald Doles

    Ronald Doles Active Member

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    I have read of people who cleaned the EGR cooler at about 100k miles and some reported that they were nearly clogged and others reported seeing very few deposits so I was wondering.

    Does this clogging seem to be worse on cars that were driven mostly in city "stop-and-go" over cars that are driven mostly highway miles?

    Does this clogging seem to be worse in cars operated from colder states where there is a lot more time below engine operating temperature?

    Our 2015 Prius V has about 75k miles on it and we are approaching that EGR cooler cleaning milestone so any input would be appreciated.
     
  2. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Infrequent or even following the 10k miles oil change can lead to increased oil control piston ring wear and clogging of the egr cooler and valve.

    Installing an oil cat can can also less the possibility of egr circuit clogging.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    That milestone is somewhat arbitrary; if it’s on your mind I wouldn’t hesitate to dive in. Do the whole thing too, including intake manifold.
     
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  4. bisco

    bisco cookie crumbler

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    we don't know the reason(s)

    best practice is regular cleaning and oil catch can. much cheaper than a new head gasket or engine
     
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  5. rjparker

    rjparker Tu Humilde Sirviente

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    Bad rings
     
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  6. bisco

    bisco cookie crumbler

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    but these simplistic explanations don't address the cars that go hundreds of thousands of miles without issue
     
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  7. Raytheeagle

    Raytheeagle Senior Member

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    Here's some backstory on our old 2010 that went 200 k miles in various climates and environments for multiple years:

    1) Prius bought in august 2009 in Richmond, VA
    • Spent 2 years there
    • Put 30k miles on the Prius in those two years
    • Commute to work was 15 miles one way on surface streets where the max speed was 40 mph
    • Climate in Richmond is mostly warm but there were times where snow fell and the summers are hot and HUMID
    2) Moved to Wichita, KS in July 2011
    • Spent 2.5 years there
    • Put 40 k miles on there
    • Commute to work was 32 miles one way and a highway
    • Climate in Wichita was warm in the summer, cold in the winter
    3) Moved to Fairfield, CA in February 2014
    • Put 130k miles on the Prius until selling it in April 2019
    • Commute to work is 38 miles one way on the freeway. Here there is stop and go traffic in addition to 70 mph
    • Weather is nice year round. Hot in the summer (temps approach 110 F in the summer). Winter temps very rarely get to 32 F
    • Oil catch can installed after the 175k mile egr circuit cleaning
    • Found our Prius consuming about a quart of oil every 5000 miles at 125 k miles
    • I did two egr circuit cleanings:
      • One at 120k miles. Found the egr cooler to be coated but not solidly plugged
      • One at 175k miles. This egr circuit cleanse was dirtier than the previous cleaning
    So in less miles, I found more plugging, but the oil consumption may have had something to do with it;).

    Hope my data helps(y).
     
  8. Ronald Doles

    Ronald Doles Active Member

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    That is very helpful. Our PriusV is a 2015 which I believe has better oil control with the newer piston ring design. At 70k miles, ours doesn't use a drop of oil between oil changes. "Knock on wood".

    My reason for starting this thread was that since my wife and I retired, we drive so little and we seldom need two cars. The PriusV is our primary vehicle and we find the battery in our Odyssey dead when we don't drive it for a month. We occasionally pull a trailer so if we were to get down to one vehicle, it would need to be the Odyssey. Driving so little now, the lower mileage of the Odyssey wouldn't really matter.

    We were considering giving the car to our daughter who lives in Florida for her daily driver. Obviously there will be shorter warm-up time and more A.C. with the Florida climate compared to our Ohio weather. The more I learn about this problem, that may not be a factor in the EGR cooler clogging problem. It sounds like this egr cooler clogging is mostly carbon buildup from consumed oil and may be more of a problem with earlier models with the older style piston rings.

    I am a little hesitant to offer her this car and then have the PriusV develop a significant problem in a short period of time or in a few miles. Her current car is now high miles but it has been very reliable.

    Thanks for your input.
     
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  9. bisco

    bisco cookie crumbler

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    maybe it's as simple as manufacturing tolerance parameters
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe Toyota's take on 3rd gen EGR shortcomings is reflected in what they revised in 4th gen: a signif increase in cross-sectional area of the components, and exhaust intake relocated to the downstream side of the Cat. AFAIK they don't come right out and say anything, but judging from their actions...
     
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  11. ChapmanF

    ChapmanF Senior Member

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    Judging by their actions, they had people reading the published engineering literature on the changed combustion chemistry achievable by taking the EGR from downstream of the catalyst, and they increased the cross-sectional area of the components by the amount corresponding to the drop in pressure when the gas is taken from the downstream location.
     
  12. Raytheeagle

    Raytheeagle Senior Member

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    How much driving does she do annually:whistle:?

    What's the mileage total on the current ride?

    70k is early on and she'll have time to pile on more miles and still be ok before egr circuit cleansing occurs;).

    I knew a courier out here who had a 2015 Gen 3 and he put 375k miles on it before a semi thought he owned the lane the courier was in:cool:.

    He never cleaned the egr circuit and also his Prius did not consume oil :).

    Another piece of data to consider(y).
     
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  13. gromittoo

    gromittoo Active Member

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    My two cents on the 2012-2014 Prius V, and the fouling rate of the EGR + Cooler:

    Oil Quality?

    Would using a top of the line Castrol "hi-mileage" 0W-20 oil make a difference compared to Walmart brand? I must confess that I have used Walmart brand 0W20 a few times. Once I discovered that Sears Auto Centers gave Uber Drivers 1/2 Price Oil changes, they did most of my changes. $42 total, and I didn't get dirty. No idea what oil they use.

    Now that my Sears Auto Center has closed for good, I decided to spend for the most expensive Castrol "hi-mileage" oil for my most recent oil change on my 2013 at 93K. $10 more than Walmart brand isn't a lot of money extra to spend, and I get just as dirty. I have not noticed oil consumption yet,

    I will post some pics when of my EGR cooler cleaning next week.
     
  14. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Walmart oil is just fine. It is widely sold under other private brands by Warren Distribution. It is a high quality oil.

    High mileage oil is the same as regular oil but infused with rubber seal conditioners. Unless you have seal leaking issues, I'd hold off on using it.

    It's not the brand of oil that's important, it's how often it is changed. As long as the oil meets the standard for SAE 0w20, you're fine.

    Clean oil helps keep the oil control rings from fouling and pass through the narrow passages that lubricate the timing chain and keeps the engine cooler. Dirt and contaminants coat the walls of these passages and slows heat transfer.
     
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  15. Mendel Leisk

    Mendel Leisk Senior Member

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    High mileage oil is distinguished from regular oil by additives that swell seals/gaskets. The bottles are NOT clear, but really: you only want to use this stuff if you've got runaway oil consumption.
     
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  16. Georgina Rudkus

    Georgina Rudkus Senior Member

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    The egr valve is easy to clean. Not so much for the egr cooler which is the real culprit.

    Four years, ago, when this problem began to manifest itself, I found salvaged egr coolers on eBay for as little as $50 delivered. Now that the issue is widely known, used uncleaned ones are near the $150 range.

    I wanted the used one that I got totally clean. I soaked and examined it every week for six weeks. Each successive week resulted in remaining yellowish solvent water. After six weeks, I got totally clear solvent fluid. The cooler was basically like a new one.

    I'd get either a used egr cooler and clean it or a new egr cooler, before I started examining the egr system.

    You will also need an 8mm e-torx wrench to disassemble the egr system. So, get one before you start.
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    That reminds me; info:
    Bad Flywheel | PriusChat
     
  18. Raytheeagle

    Raytheeagle Senior Member

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    I was using Mobil One 0w-20 pre oil burn, so that is some pretty good stuff;).

    After that, I clubbed up and began using 5w-30 Red Line:).

    Did help maintain the oil burn, but then at the end I went to Pennzoil Pure Platinum 0w-40. Said the same Mai raining of the oil burn, but at a cheaper cost(y).
     
  19. Georgina Rudkus

    Georgina Rudkus Senior Member

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    You could be damaging your engine to the point of starving the delivery of oil to the timing chain and also be reducing the cooling effect of the oil as a higher viscosity moves slower to reduce the effect of the flow of oil that also cools the engine.





    VW switched back to timing belts in their engines due to restricted oil flow, since timing belt systems fo not require narrower oil flow passages. Timing chain damage in VW engines is legendary.
     
    #19 Georgina Rudkus, Jun 17, 2021
    Last edited: Jun 17, 2021
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  20. Kenny94945

    Kenny94945 Active Member

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    Post 16, say Georgina, what solvent did you use?
    I liked your idea/ cleaning technique.