Start-stop driving and EGR maintenance

There are lots of reports of 300,000 mile Prius taxis around the world running well on original battery and with only maintenance per the official schedule. overall, it seems that Prii that are driven a lot of miles per year hold up quite well

Actually, I've wondered (sort of) the opposite. Do short trips (which use periods of electric only power off and on more than extended highway driving does) result in lower risk of engine overheating and blown head gaskets, even if the EGR cooler gets clogged.

Specific to your question, I don't know how you would determine what factors affect EGR cooler clogging unless someone kept a running tally of people reporting results of EGR system cleaning including year of vehicle, mileage, etc.

It would be great if we could find a taxi or uber driver who has cleaned their EGR system at 150,000 to 200,000 miles or later.

 

I'm pretty sure there was thread a while back, maybe a New York cabbie, or the guy had cabbie friends. IIRC it was two cabs around 200K miles, one under, one over? The EGR's were a carbon gong show.

 

i thought it was mostly gen2 high mile taxis.

regardless, i don't know if we have enough info to make conclusions

 

I just checked mine (well, the manifold and the pipe, and the rest by a Techstream flow check) at 154,000, and there was barely anything to clean, maybe a paper-thick coating inside the pipe and manifold passages that I lackadaisically cleaned out to feel like I'd done something.

I don't know what that says; I've owned the car for the last 4 years / 44,000 miles with a quite short commute, throwing in just a few longer (few to several hundred mile) trips a year.

 

My wife and I have done a lot of overseas travel. Airports everywhere have Prius taxis lined up including plenty of gen 3 and Prius V.

We actually had a trip to northern Italy booked for April. It was cancelled, of course. We won't be going overseas again for a while.

 

Not sure what kind of driving @ArmyChief was doing, he posted some pics of his around 156K miles, and the EGR capillaries in the intake are pretty knackered. Number 4 (closest to EGR pipe connection) is the clearest, and number 1 is pretty much sealed off with carbon. That's where the predominance of head gaskets seem to fail too, coolant passages between cylinders 1 and 2.

Intake manifold EGR ports clogged - PICS | PriusChat

 

Yeah, those were the pics I had recently seen that made me curious to see the inside of my manifold.

I guess there's been something way different about my car's life compared to ArmyChief's, but what, I don't know.

 

Ours wasn't that bad either, albeit only about 44K miles when I did the cleaning. Don't regret it: I think even modest carbon coating in the cooler is impeding flow some, and insulating cooling fins. Doing it the once, you've got all the tools for a revisit, and the know-how that it'll go faster.

One tip: once you've got the bottom bracket off the cooler, leave it off. There's still plenty of support. I was bored the other day, so decided to remove just that bolt (I'd put it back before, more fool me...), it took me a solid hour, unbolting adjacent conduit brackets, playing around with various ratchets, extensions, sockets.

 

I would believe that taxis are being propelled by ICE over longer periods of drive time keeping ICE at optimal temp burning fuel in the chamber much cleanly. Short drive temp won’t burn fuel completely up with lower engine temps leaving residue. I get less catch can contents now once my drive became 100 miles a day, compared to what it collected the 12 miles a day.

 

understood, but that doesn't make them high mile

 

my engine only runs to warm up every 124 ev miles. will be interesting to see inside some day, but i only have 20,000 hv miles, so don't ask me to look.

 

It is interesting how we humans can have access to the same information and come to different conclusions. You may be right that reports of high mileage Prii was of 2nd gen, but conclusion is that since there are many 3rd gen Prius taxi's then a portion, probably a significant portion since gen 3 was released 11 years ago, are high mileage.

Here is the conclusion that follows the one above. If Prius taxis around the world had experienced a high rate of blown head gaskets, we would have heard about.

Anyway, that's how I see it. (i have been wrong before).

 

and the number of repairs could be different. iirc, gen3 has been a huge disappointment to fleet owners who started with gen2, but i hahe also been wrong, mostly.

 

Agree. Post didn't say which generation of prius, it can be 2019 prius so less likely to be high mile.

 

First video here is a cab:

New head gasket replacement video from Gasket Masters | PriusChat