Is There A Best Case Scenario Which Minimises Carbon Build Up In EGR Circuit?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by richard1540, Jun 29, 2026 at 3:50 AM.

  1. richard1540

    richard1540 Junior Member

    Joined:
    Aug 20, 2019
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    Vehicle:
    2011 Prius
    Model:
    i-Tech
    Just wondering what is the best driving style to minimise carbon build up in the EGR circuit?

    Sustained Freeway/Highway driving vs City stop and start?

    Higher octane gasoline (petrol) (91-92 (95 RON in Europe or Australia)) or (94 (98 RON in Europe or Australia)) or an Ethanol blend?

    Anything else?

    I’m in Australia and my 2011 Gen 3 has 106,000 miles (170,000 kms). I’ve been trying to find a mechanic to to take the EGR cooler pipe to see if there’s a build up but they don’t want know about it given the work to get at it. I have done mostly highway/freeway kilometres and always use 91-92 or 94 gasoline. The fuel lid specifies 95 (91-92) minimum and that it is ethanol compatible ( which i’ve never used).
     
    #1 richard1540, Jun 29, 2026 at 3:50 AM
    Last edited: Jun 29, 2026 at 3:57 AM
  2. ASRDogman

    ASRDogman Senior Member

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    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    It's a waste of time to look at that huge pipe. The cooler is what clogs. Those passages
    are small. Same with the intake manifold.
    Changing the oil/filter at 5000 miles helps, not driving the Prius like an F1 car helps.
    Installing an oil catch can helps. Nothing will stop it, it's a by product of engines.
    Highway miles are better for the Prius then city driving.

    Using a higher octane than what Toyota calls for is just wasting your money. It's not going to help
    the engine at all. Quality of the fuel will.

     
    #2 ASRDogman, Jun 29, 2026 at 7:09 AM
    Brian1954 likes this.
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