Prius shakes cause? Clogged EGR or something worse

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Bridger, Mar 13, 2025 at 2:49 PM.

  1. Bridger

    Bridger Junior Member

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    2011 Prius with 170k and bad oil consumption issues. The engine shakes and rattles. I’ve had this issue before on start up but it would usually only last a few seconds. I cleaned the EGR system and then it went away.

    Now I’m getting this rattle and shake when the car is parked and idling for long enough that I shut the car off for fear of further damage. It also shudders a bit around 25 mph with gentle pressure on the accelerator or while coasting. Is this just my EGR system acting up again or is it something worse? If it’s just EGR, why is it coming on so badly this time around?


     
  2. PriusCamper

    PriusCamper Senior Member

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    Has it been running low on coolant?
     
  3. Bridger

    Bridger Junior Member

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    Nope. Coolant level is all good.
     
  4. rjparker

    rjparker Tu Humilde Sirviente

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    If it's the egr you have a sticking open egr valve. Normally it is closed at low rpms and wide open throttle. Toyota has a revised egr valve and ecu software.

    Newer EGR Valve
    Egr valve updated Kit 04004-58137
    With 25620-37120 Updated egr valve
    IMG_7791.jpeg

    Blocking the egr flow is the definitive and easy test for an egr valve sticking open.



    The reality is egrs don't cause a massive metallic sounding rattle. Even without obvious coolant loss because it only takes a few drops. So if the egr block test shows no improvement, move on to a cylinder borescope test.
     
  5. PriusCamper

    PriusCamper Senior Member

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    Most common problem with Gen 3 engine shaking/start of engine failure is coolant loss due to head gasket failure between cylinder #1 & #2... If you have no coolant loss, I'd recommend focusing on examining/replacing vacuum hoses, which may have failed.

    Can you please elaborate on oil loss issues? How many miles for each quart of oil lost? Gen3 used high MPG piston rings that wear out prematurely, but I've never read that related to engine shaking.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Presumably first cleaning? Way too late, almost certainty the head gasket is letting go, leaking coolant into combustion chambers. Confirm with borescope inspection.
     
  7. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Concur.
    A clogged EGR is the equivalent to high cholesterol.
    The 'death rattle' is, in many cases the resulting heart attack.

    A 'minor' heart attack....isn't.
     
    Mendel Leisk likes this.
  8. Bridger

    Bridger Junior Member

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    Oil loss is quite a lot. About a quart every 500 miles. There's a small leak in the system as well, but I don't think much of the oil loss could be attributed to the leak.
     
  9. Bridger

    Bridger Junior Member

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    First cleaning happened at about 120 or 130k miles. We bought the car at just under 120k. I have probably had to clean egr twice since that first cleaning?
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Just from what I’ve seen, every 50k miles would be the longest I’d stretch it. Your runaway oil consumption is not helping, likely accelerating the carbon build-up.
     
  11. rjparker

    rjparker Tu Humilde Sirviente

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    The runaway oil consumption is the reason for actual egr codes and clogging. It can also cause the egr valve to stick.

    There is no harm in checking off the egr valve using the egr block flow test. Egr sticking or egr cooler clogging will code quickly since the system is checked almost every drive cycle. The symptom of egr sticking open is a stumbling not quite smooth engine. No loud noises or shaking. A clogged egr cooler has no symptom other than a code. However your video falls into the "massive metallic sounding rattle" category (damper slipping because of misfires).

    It's time to carefully evaluate the car. Has the brake booster/master cylinder failed yet? Are there catalytic converter efficiency codes? Has the hv battery coded or shown fast charge discharge cycles or forces the engine to run at stoplights most of the time? One or two of these are expensive and combined with the engine might justify getting rid of the car.

    The good news with other common concerns still good: A properly rebuilt engine can restore the powertrain to like new condition for the next 200k miles. You buy and swap in a a rebuilt engine - not yours. Think of it - no leaks, no oil consumption, no start up rattles or stop light rattles. Like almost new buyer enjoyed for the first 8 years or 150k miles when hybrids pay dividends.
     
    #11 rjparker, Mar 14, 2025 at 12:45 PM
    Last edited: Mar 14, 2025 at 6:04 PM
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    Mine didn't get that memo.

    For the oil consumption, the attached TSB's, while not applicable due to miles, has useful info. Also, last link in my signature is the full engine section.

    This video (multi-part) video, brought to my attention by @rjparker, outlines a piston/ring replacment.

    [


    (I think part one is removal, hard to find.)
     

    Attached Files:

    #12 Mendel Leisk, Mar 14, 2025 at 12:49 PM
    Last edited: Mar 14, 2025 at 1:11 PM
  13. rjparker

    rjparker Tu Humilde Sirviente

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    You had egr codes? Be honest.
     
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    Of course not. If you wait around for P0401 and cold-start shakes, you're screwed.
     
  15. rjparker

    rjparker Tu Humilde Sirviente

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    P0401 is not really a precursor to head gaskets or you would see that cause and effect on Corollas and gen4s. Gen3 oil burners do code quickly which is why Toyota had a campaign and an updated egr part. Certainly excessive oil burning has hg ramifications starting with preignition (pinging) caused by carbon buildup.
     
    #15 rjparker, Mar 14, 2025 at 2:34 PM
    Last edited: Mar 14, 2025 at 6:04 PM
  16. Bridger

    Bridger Junior Member

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    So the shop I took it to says there's a compression issue. Cylinder 3 is putting out 27lbs of compression while it's supposed to be something like 100. I'm new to this shop, but I've heard good things from reputable sources. They're saying it would be about $5k to replace the engine, parts and labor. I don't have the mechanical know how to diagnose the compression issue to confirm it is what they are talking about. Nor do I have the skills and abilities to put in a new engine myself. The car has felt like a bit of a lemon since we bought it at 120k miles about 4 years ago, but I wonder how many of its issues would be fixed with a new engine. Unfortunately, for the first time in seven years, we are in a place where my wife and I both need a vehicle daily so if we go the new engine route, I will likely need to go out and buy something cheap to get us by in the meantime. It has a salvaged title so I'm not sure what kind of value it holds in its current undrivable state versus if we put the $5,000 in it for a new engine. Anyone have suggestions or advice on how to decide what to do here?
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    I suppose you can see it that way. My take:
    I'm informing OP that EGR cleaning was too late, another cleaning won't "reverse" what's happening, and to concentrate on head gasket assesment.
     
    #17 Mendel Leisk, Mar 14, 2025 at 2:57 PM
    Last edited: Mar 14, 2025 at 3:54 PM
  18. Paladain55

    Paladain55 Active Member

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    For 5k i would just take the loss. Buy a new car. These are cheap cars on facebook marketplace. One thing to learn is keep the egr clean or delete it, and change the oil every 5k.
     
  19. rjparker

    rjparker Tu Humilde Sirviente

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    Sounds like it bent a connecting rod which happens on gen3 Prii with a serious hg leak.

    The economy solution is a used in Japan JDM engine, maybe $1300 plus installation. However the other hybrid budget killers are still possibilities.

    Don't buy another low cost hybrid. Real value and low cost of ownership is far more likely with a Corolla, Civic or Camry in your price range. Any shop can work on it, there are decent aftermarket parts and you still get decent mpg.

    It's always a good idea to spend $200 with a trusted shop to check out any used car before buying.

    If it's any consolation, your experience has been repeated hundreds of times on gen3 Prius engines. One shop near me has done a thousand replacements in the last four years.