Verification of EGR cleaning

Googling this:

How much carbon coating on egr cooler fins is needed to impact cooling ability

the AI summary is interesting.

 

Is our primary concern, temperature or flow of the exhaust gases re-entering the intake manifold?

 

Both? The cooler is quite the contraption.

 

I generally agree, but since one version is so much easier (no vowel) and still delivers above 21 kPa flow, it’s still relevant.

The cooler will look terrible even if brand new, after some hours of engine running. That does not really indicate a bad flow…

I have still failed to see any validation data of actual flow thru this cooler. This is likely why Toyota prefers blowing it with pressured air, since it will indicate flow exist - if the back is removed (I did not remove the back of the cooler since those bolts require wiper/cowel removal. So much ash blew out in the front (use mask)).

Why are the exhaust gases cooled? Likely engineering explanations are due to the manifold is plastic, the delta between normal airflow temperature (hundreds of degrees difference) is very big, and with g3 this was a new tech. How do newer EGR treat this..? This is like a beta/alpha version in my analysis.

The trick to block the throughput at the pipe is very smart and is done by Toyota to separate the vibration issue (my plug-in had massive vibrations at 30-60 kmh when car was bought at 270.000km) from the lovely head gasket issue.

 

This is true, but the super small passages of the manifold are much worse in that regard (again, since they can have added oil. This does/should not exist in the cooler environment (normally)).

 

How many hours do you think?

 

One?

 

I wish I had checked the non-continous EGR monitor flow value before cleaning, would have be interesting.

My plug in 2013 had no codes or indication of issue in the ECU, but the engine behaved very bad with morning rattle and massive vibrations when engaged at all speeds. All gone.

Cheers to @Mendel Leisk and priuschat alumni - and YT folks (merv et al) helping!