Any cases of Prius c EGR clogging and/or head gasket issues?

While Gen3 Prius Engines and Prius C engines aren't that different, in being on here every day I've yet to see an article for Prius C EGR valve cleaning, nor a Prius C head gasket blown post... But I'm not on all the forums so... I do remember once that I presumed that Prius C was the exact same as Gen3 with EGR issues and someone corrected me in a way that I agreed with and stopped lumping them together, but I don't remember the specifics.

 

...in the USA maybe.

Keep in mind the Aqua, root model of the c, was the most popular car in Japan for years and was still in the top 5 for 2020. It's the Japanese F-150.

You might not be finding cases due to a language barrier, but I suspect what's really going on is that the EGR on the c just isn't clogging up. And because it isn't clogging, the head gasket is not being subjected to overpressure. Less overpressure combustion = fewer breached gaskets.

Remember, EGR has been a "consumer grade" engine management technology going back to the early 1970s. Plenty of engines have been equipped with EGR and driven for decades without clogging.

It is important to remember that a cloggy design is the exception and not the rule.

 

Lol, I'll never look at a Prius C / Aqua the same way again!

 

Er, can't directly. Which part of the EGR? It is fundamentally a passageway connecting the exhaust manifold (on the back of the engine) to the intake manifold (on the front) though the Prius version also includes a heat exchanger and a flow control valve, possibly more.

I conjecture that the exhaust stream offered into the heat exchanger is too "dirty" which allows constriction by particulate accretion. If they tapped the exhaust from elsewhere in the system, the cooler might never have fouled.

 

I thought Prius c engine was close to Gen 2: 1.5 liter displacement, and only a rudimentary EGR system, relatively bullet-proof.

 

Gen 2 used the 1.5 liter 1NZ engine and no EGR whatsoever.

The c uses the "same" 1NZ engine, updated with an electric water pump and cooled EGR like the rest of Gen 3, as seen in that video.

 

Ok, so egr closer to 3rd gen, thanks.

 

Right but what's feeding that heat exchanger?

Is it the "cool and dirty" flow coming right off the cylinder head, or is it the "hot and clean" exhaust from the catalyst?

I gather that this forces them to choose between contaminant accretion from the former, or extra cooling load from the latter.

 

The liftbacks didn't switch to catalyzed EGR until Gen 4, MY 2016. The c was born around the time of the mid-Gen 3 refresh.

The introduction of catalyzed EGR to the industry doesn't seem to have been just somebody at the water cooler saying "would we get less gunk if we tapped the pipe here?", but more like a spanking new EGR regime in its own right. The catalyst changes the chemistry, the changed gas does different things to combustion when returned to the cylinders, and the pressure is also lower, having dropped across the catalyst. Engine design and ECM algorithms re-tailored for it. Journal papers about it. Maybe some of those dates would indicate whether it would have been even a thing at the time the c was being designed.

 

Do they have a pipe?

 

Why, yes ... yes, they do ... as was covered in some of the 'idle chatter' earlier in the thread. And shown in a rather large photograph in #12.

 

For that matter - do we have external catalytic converters?

 

Yes, there is a catalyst. Relax, it's much, much smaller than the one everyone wants to steal. When they start catjacking every random Chevy & Honda on your street it'll be time to worry.

I'd be happy to remove and inspect mine to add to the data pool, but I'll probably wait until 50 or 60k miles to do it.

 

I do have a 2012 Prius C with about 110k miles. But I am NOT familiar with the EGR system, so don't want to mess with it unless there is a Youtube for me to follow.