Prius Gen 3 Major Maintenance: EGR, manifold, spark plugs, Oil Catch Can

Looks like you’re setting out for a picnic.

 

Lol, yeah placemats and all.

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Very neat handy work.

 

The stainless steel 1/2 inch NPT 90 degree to 3/8 inch (10mm) barb fittings came in today.

Pictured one fitting into the 3/4 inch ID hose needed to fit onto the intake manifold.

The 90 degree bend will make it easy to go down to the oil catch can mounted down low on the crossmember.

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Do you all think there is any point to cleaning out just the EGR pipe by itself? Seems like a much much easier task than removing and cleaning the whole assembly

 

It would be like changing half the engine oil, and not the filter either.
The pipe is minor. The cooler is what gets clogged the most....

 

The intake manifold has EGR passages too.

 

If I only had time/energy to do one part of the EGR path, I would do the small passages in the intake manifold, and ask the car's EGR flow monitor for its opinion of the rest of the system.

The reason for breaking it up that way is because (a) the flow monitor can't tell you what's going on with those manifold passages, because there are four of them and it has only one sensor, and (b) having those passages clog up different amounts may be kind of pernicious, because the car will use the one sensor to control the valve to get a certain overall flow, but that will really mean some cylinders get too little and others too much.

In fact, that is the way I broke it up; I cleaned the manifold a year ago, kept my eye on the flow test numbers, and did the rest of the EGR system this summer.

The manifold is a much less exhausting job.

 

Clean MAF sensor (in air filtration set): used MAF cleaner. Only sprayed directl

Did all my cleanings but this, no idea where/how to spray in the air filtration system

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The MAF sensor is bolted on around back of the engine air intake, just a bit upstream from the throttle body: unbolt it, disconnect wire harness, remove it from air intake and give it a spray with MAF sensor spray, which comes in a can.

CRC makes one such spray. I did ours once, but don’t think it was necessary; it looked very clean to begin with.

 

Tips:

• ~Tip 2: There's a 12mm bolt at the EGR's bottom bracket that is tough to get to. Get some sort of socket combination that gives you 3-inch clear space.
• Pic for Tip 2: View attachment 164242

Hope this helps![/QUOTE]
Regarding the 12mm “bolt from hell”, in found removing the studs from the exhaust pipe simplifies removal. I just leaned over from the passengers side.

 

Is there any guide for 2 gen?

 

In 2017 the EPA reduced the sulfur in gasoline from 80 ppm to 10ppm. It's called the "Tier 3 Motor Vehicle Emissions and Fuel Standards". They claim by reducing gasoline sulfur to this level results in "70% reduction in per-vehicle particulate matter (PM) standard".

https://nepis.epa.gov/Exe/ZyPDF.cgi/P100HVZV.PDF?Dockey=P100HVZV.PDF

Perhaps only one cleaning is needed for gen 3 Priuses?

Not sure what Canada's gasoline standards are.

 

I have a 2013 Gen 3 and I did the entire EGR system & manifold clean out. The radiator thing was clogged, and a lot liquid-ish oil in the recess below the throttle body was present. So they did not fix it in mine. But it’s all good now.

 

Liquid-ish oil below the throttle body is always there back to the very first generation of Prii. My Gen 1 had it. The car just does that. There are a bunch of posts around here with people going to great lengths, catch cans, even dual catch cans, or what not, to try to have it not be there, and meanwhile the world's other several millions of Prius drivers just drive the car.

Because it was present in Prius generations before Gen 3 added EGR systems, and in both the 1NZ and 2ZR engines, it doesn't seem likely to be related to the EGR system.

 

you know a good test would be to put an ounce of water in the bottom of the intake manifold and to see what happens.

 

To what extent does using top tier gas or an additive like Techron affect buildup of carbon in the EGR system? If it works to keep combustion chambers and valves clean, why wouldn't it help keep the EGR system clean?

 

ICE is never 190F or hotter at all times when burning gasoline then factor in when Prius goes in EV and ice cools down consistently.

 

I doubt it. Exhaust gasses are diverted from the (exhaust) manifold, up a pipe, through the EGR cooler/valve/pipe and into the intake manifold. A gasoline additive is not going to take the soot out of the exhaust. I suspect the amount of soot is increased too, by the PCV system's propensity to dump oil/water vapours into the intake manifold. That pool you see at the bottom of the intake may only be the part that settles; a lot might remain vapourized, blow right through, into the combustion chamber, combusted and exits as even more soot.

 

I imagine the fuel additive is some kind of solvent that is able to have a cleaning effect on the intake valves and cylinders. By the time it exits the exhaust valves, after combustion, it has been turned into ... exhaust.