Professional EGR Cleaning Resources

I recently spoke with a Prius mechanic and that's what he works on: Prii. He's not located in my area. Anyway, I asked him about EGR cleaning and all the other bits involved as well for my Prius that has less than 40K miles.

He said, "I would not consider cleaning the egr until 100k miles. The last 2 EGR cleanings I did (both in 130k range) were dirty, but neither was close to being clogged. They both could have easily gone 150k miles before their cleaning. No, you do not have to clean the EGR every 50K miles, that's not necessary IMO."

 

it shows how varied the experiences are

 

Good insight here. My Prius is 160k. Just cleaned it for the first time. Considering buying an ultrasonic cleaner to really get is deep cleaned. Will keep this in my notes.

 

Don't go over board....
The 'pinch down spots' are in the tiny individual intake ports.
Those can be made new in a few minutes with a small brass rotary brush on a drill. After the intake manifold is on the floor, that is....
The rest of the system can handle the patina of crud on the walls of the passages.

 

That's a vital set of facts that should be disclosed, whenever you're giving your opinion to other Prii owners about the EGR and related systems.

It's not standard protocol for a Prius owner to be cleaning the EGR before 100K miles, and certainly not every 50K miles. That you choose to clean your EGR system often, is not something recommended by Prii mechanics, and advising other owners to clean their EGR systems often, which isn't necessary, increases maintenance costs for fellow owners.

 

Had anyone tried removing the EGR completely like Prius sold in Brazil or other parts of the world? It probably solves the cleaning completely

 

Yeah, I'm not out to make it 100% new straight from the factory clean. I used just what you suggested, a small brass rotary brush and my drill and got the bulk of the crud out.

 

I will focus on the EGR valves, pipes, and intake manifolds. The cooler is too much time to fidling around if it is not clogged.

 

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And even it it is starting to clog a bit, at least it will decrease the EGR flow EVENLY.
The head gaskets failing near the #1 and 2 cylinders is due to the UNEVEN flow of EGR gasses, theoretically.
The 1 and 2 ports are farthest from the source of the flow and have more time to cool and condense the crud in those small intake ports.

If the overall flow gets restricted enough,,,, there's a code for that. Correct?
The system compares MAF and MAP sensors and see the lack of EGR effecting the MAP reading.
Is this correct?

OK, then what happens when the EGR gasses are 'hotter than expected'?
Would the plastic near the EGR pipe start to show signs of melting?
Clamp a thermocouple on the 90° EGR pipe and try to get temp data. Maybe before and after your spotless cleanings. good luck....

I see some other engines with insulation wrap on EGR pipes trying to keep the EGR gasses as hot as possible.

 

The criterion johnHRP mentions is "if it is not clogged", for which the car's routine EGR flow test result would seem to give a pretty direct answer.

That is, a good flow test result is a pretty direct answer. A lower flow result could be lower because of clogging somewhere else, or because of a rut in the valve rotor. On the other hand, if you've checked and there's no rut and the other stuff isn't clogged, then your low flow result can be pinned on the cooler.

That doesn't directly address Mendel's concern about patina reducing cooling, which johnHRP might not be as concerned about. How concerned about it one should be seems an open question. Bill Norton's suggestion of comparing clamp-on thermocouple readings before/after cleaning seems like a sensible approach; I haven't seen that anyone's posted such results to date.