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

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.

 

Just clean it. Shouldn't have to be, but Toyota screwed the pooched, and doesn't want to own up.

 

The op said he can't find a shop that wants to do it.

The best approach is to keep your 2011 from burning oil. Oil burned through the combustion chamber creates excessive carbon which clogs up the catalytic converter and will fully clog up the egr cooler.

If it is already burning oil (which is most common after 125,000 miles) the engine needs revised pistons and rings. This problem was acknowledged by Toyota years ago and changed free if oil burning became excessive while still in the powertrain warranty.

Many of us simply view the automatically calculated egr flow on a regular basis:


A good egr flow is typically 18-22.

This comes from the bluetooth phone app "Car Scanner" or other obd2 scanners including Techstream. The car will code if this periodic test fails.

Another easier to achieve egr related maintenance is to have a shop replace the intake manifold which may be the only credible egr flow clogging concern.

If head gasket issues are the real concern, the egr cooler clogging theory is not shared by Toyota, their mechanics and apparently your guy.

If existing stumbles and rough running are your concern, an egr block flow test is easy for your shop to accomplish and can determine if the egr valve is sticking open, a failure mode that sometimes happens and was also covered by Toyota for a period.

Egr block flow test

A revised egr valve is available as well.
Valve Kit With Gaskets
04004-58137 - Toyota Parts Deal

 

1) Minimize oil consumption;
2) Minimize conditions that lead to burning a rich fuel-air mixture while EGR is active.

 

And install an effective oil catch can.

 

Just editorial: an imperial pint? A full US pint is roughly 473 millilitres (Google ml in a pint). Maybe just stick to litres lol.

again, it’s conflation to think that no oil consumption equals no EGR clogging, a tight engine still puts out carbon. The 3rd gen EGR design is the main problem: it’s undersized, gets its exhaust gas upstream of the catalytic converter, and consistently clogs up. It’s very evident Toyota did not test it properly, before going to production. The revisions in 4th gen EGR design illustrate what they missed.

I wouldn’t go there with the Prius, if that’s the thought. My 2 cents: maintaining it, keeping it clean and functional, is the way to go. “Blank/disable” is equivalent to “clogged”.

With 106k miles, it’s all eminently cleanable. The only thing I’d even entertain replacing is the cooler, but that’d come clean in a few hours with a series of potassium hydroxide solution soak-and-rinses (10~15% by weight, KOH to water, following safety guidelines), which can be happening while you’re dealing with the rest, which is doable with brake cleaner, rags and brushes.

you can easily bang this out in a weekend, with no replacement of components.

Second time around I splurged, replaced the intake manifold gaskets, around $35 CDN IIRC.

 

See if you can find a used oil cooler from a junk yard.
There are no moving parts, and it's stainless steel.
Oven cleaner and a pressure washer does a good job of cleaning it out.

 

Egr cooler. Buying new online is not too bad as the prices have come down over the years. There are no aftermarket or counterfeit egr coolers to worry about.



You may get a significantly lower price since you don't have our excessive import taxes.