EGR Circuit Cleaning/Swap - My Experience

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by EfficiencyNerd, May 25, 2019.

  1. EfficiencyNerd

    EfficiencyNerd Junior Member

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    Hi all,

    Last weekend I performed this surgery on my 2010 (formerly @eric1234 's Prius), and wanted to share my experience. My Prius has about 184k miles/296k kms.

    My first step was to order a replacement valve/cooler to swap in, since I was not wanting to take the time to clean it out during the operation. I also expected I would need to clean them both out once they arrived, and I was correct! Following other posts on here, I got some Brakleen as well as Oxi-Clean and set to work. (I did not use oxi-clean on the valve.) After several nights soaking in oxi-clean and running warm water and Brakleen through the cooler, I decided to get some wire to get the last few slots open. I've heard a pressure washer works wonders, but I was a bit too scared to try it. ;) The valve cleaned up fairly quickly with a wire brush and Brakleen.

    After watching through various @NutzAboutBolts videos (thanks a ton!), I decided I might as well also clean out the intake manifold and do a partial coolant change (so the level was below most hoses) all at the same time. I used parts of 5 different videos in the process - the coolant drain/refill, the spark plugs (to remove windshield wiper assembly), the egr pipe, the egr cooler & valve, and the intake manifold.

    The hardest part for me was getting the egr cooler off (no surprise there). However, I did have to improvise at one point - when I was taking the front E8 torx bolt off (shown here in Nutz's video), I stripped the bolt because it was so tight coming out! I messed around for a while trying to get the whole assembly off together, since it was loose and I could slide it back and forth on that bolt. Then after taking a lunch break and taking a look at my replacement one that was going in, I decided to try disassembling the valve and adapter from the cooler. It turned out I had just the right adapters and extensions, and I was able to separate the pieces, which allowed me to get them out. So it is possible to remove the EGR assembly without taking off that front E8 bolt, although it is a pain in the rear to do it that way.

    Nothing in the circuit was completely plugged yet, which was a bit surprising to me but I'll take it. I could see through a couple of the passages in the cooler which I did not expect. Regardless, the cooler going in had every passage clear, so it was definitely a worthwhile job. The pipe, adapter, and intake manifold also had quite a bit of gunk come out of them with brake cleaner and wire brushes.

    After putting everything back together, I refilled the coolant and put the car in maintenance mode. It started quite hard and with a bit of complaining that very first time, but once it was running it was fine and had no warning lights whatsoever, and it starts just fine now. Perhaps the initial complaining was a bit of loosened gunk that got pulled in over the first few firings.

    All told, it took me about 8.5 hours, including a half hour lunch break. I was very glad to have gotten a replacement cooler and valve ahead of time!

    After the swap, I've noticed the engine runs maybe a tad smoother, and mpg might be 3-5 better but it's hard to tell since that could be just the weather getting warmer up here.

    Huge thanks to @m.wynn for initially suggesting (almost a year and a half ago!) that I undertake this operation. After significant procrastinating, I finally got it done. :) And of course, huge thanks to NutzAboutBolts and his videos - couldn't have done it without them.

    Anyone want my old cooler/valve? It comes pre-soiled so you can learn how to clean it ;)
     
    Boffin, Prieth, m.wynn and 8 others like this.
  2. Raytheeagle

    Raytheeagle Senior Member

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    Glad it worked out for you ;).

    8 hours for the first time isn’t bad at all for the job. But that was aided by the swapable parts:).

    Good luck selling the spare(y).
     
    m.wynn and RightOnTime like this.
  3. RightOnTime

    RightOnTime Senior Member

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    Welcome to the club!


    iPhone ?
     
    m.wynn and Raytheeagle like this.
  4. ChapmanF

    ChapmanF Senior Member

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    Care to gather some EGR flow data with your newly cleaned bits, to add to that thread?
     
    mjoo likes this.
  5. EfficiencyNerd

    EfficiencyNerd Junior Member

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    Interesting thread, I may have to do that! I did recently get a Vxdiag but haven't yet gotten it working. Perhaps this is a good excuse to fiddle around with it.
     
  6. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    Everybody seems to have trouble backing that stud out of the engine, maybe poorly threaded?
     
  7. CR94

    CR94 Senior Member

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    I might. Any clue how difficult it would be to ship south over the border?
     
  8. EfficiencyNerd

    EfficiencyNerd Junior Member

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    Sent you a PM... shipping across the border is always hard to say if they'll ding you with a duty fee or not.
     
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