My intake ports @ 150k miles (NASTY!..)

i used to adjust the valves on my '72 fiat once a week, whether they need it or not. but i was 20 and really bored

 

Yeah I think the EGR is ultimately what's causing the carbonized cr@p build-up in the intakes. Maybe the oil mist delivered to the intake manifold by the PCV circuit is going through the combustion chambers, burning, and coming back via the EGR as well.

 

Was that the software update, to protect the inverter from sudden acceleration damage? We had that with little ill-effect, the only thing really noticeable was a slight increase in propensity to slip into electric-only. But there were a few reports of dropped mpg. Maybe the update was problematic, could be screwed up??

 

Long time Avi, what do you think causes the head gasket failures in the gen3?

 

@mjoo has postulated that clogging EGR results in markedly raised engine temperatures, and that can't be good for head gaskets.

And the PCV oil dump is probably abetting the EGR build up?

 

I'm planning on pouring a half a quart of motor oil in my intake just to prove oil catch cans aren't necessary.

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Into your turd gen, correct? You only show the '05 in your profile. I don't think anyone here has any beef with gen 2 intake or PCV design... But I'm up for seeing your test data even in a gen 2. Even with turd gen, I'm not convinced the oil catch can is necessary.

 

Definitely not oil in the intake manifold. I must have done at least 20 head gasket replacements. Some of them had bad water pumps. Most of them didn't have EGR problems. I think it's just a design flaw. I've had people tell me they read online that it's a problem with 2010s while I've done two 2013 head gaskets, one with 153K and one with 152K.

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Shouldn't a bad water pump throw a code or warning light before it's too late?

 

One thing: the Manifold Absolute Pressure sensor is pretty much swimming in the (PCV supplied) oil, down near the bottom of the intake manifold. Not sure if that matters; it does seem pretty robust.

Too, the oil that's collecting in the Intake Manifold is just the stuff that condensed and hung around, didn't carry on to the combustion chamber.

 

My software update didnt do much for the car but lower the mpgs. It used to stay in electric for a long time even highway speed. Now it relies mainly on the gas engine. The battery in ev mode wont stay in long over 12 mph. It does however hold a charge longer. When i bought the car at highway speed it used to buck alittle going 75mph during electric operation and after the update the magic of prius mpg was gone. But has been reliable.

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Video record it and post it on YouTube. If it goes kaput, we’ll need to see that also.