Thanks to all of you, I took a dive into my 3rd gen Prius. 2012 with 139k miles on it. I didn’t have any codes or problems (other than a few knocking situations in the coldest mornings of January), so this is all preventative maintenance. Never had any mechanical experience but I watched @NutzAboutBolts about 100 times before and read as many Priuschat forms as possible. I did it all in one day, 9 hours straight work in 100 degrees heat with high humidity. The EGR cooler and EGR intake ports were about 90% clogged. Soaked in purple power for 30 minutes, blasted with pressure washer for 10 minutes on both sides and soaked in brake cleaner. Came out perfectly clean! Here’s all that I did. Replaced intake manifold Replaced EGR valve Replaced PCV valve Cleaned EGR Cooler Cleaned EGR pipe Cleaned throttle body Cleaned MAF & MAP Set up OCC Getting the ECU updated for the TSB regarding the EGR here soon. Thanks for all the active members here that post in detail about their experiences and findings.
Thanks for the report! Did you happen to note down the ECM's EGR flow monitor value from before or after the cleaning or both? How did you obtain the 90%-clogged figure?
I don’t have tech stream so I unfortunately cannot provide any data. The 90% was just from putting a flashlight on the back and seeing how much light was coming through. It was mostly a rough estimate, but regardless it was almost completely plugged with carbon.
In that EGR flow thread, people have reported using OBD-II tools other than Techstream to get the flow monitor value. Any tool, smartphone app, etc., that is able to do "mode 6" monitor result queries can do it.
Just remember the OCC will help cold start since condensation and blowby will accumulate in the occ than the intake manifold. Also egr cooler needs constant cleaning do not wait since if it gets plugged you can cause the cylinder to get to hot and the combustion can cause a gasket failure.
One thing with those "before" pics of the cooler, if you're using a phone, tap on the dark interior, or whatever your phone does to determine what should be exposed correctly, because otherwise it sees all that bright flange and the interior's nothing but black. Which it is, lol, but... Or..., look into the Hipstamatic app. Besides neat retro effects, it allows very easy locking of exposure. And focus.
I still have the old manifold and valve so I will take better photos of them. Didn’t bother to do anything to them.
Yeah it's an inside joke. Can't remember who declared me nuts though; @Grit maybe has it in his on-deck quotes??
