Oh Crap

So the first thing to do is to get the car warm and get it on the mark of the cooler Mark h or hot or whatever after that's achieved and you notice you're not losing cooling or whatever couple hundred miles whatever it is see what you got check your plugs go from there

 

Sometimes these head gasket symptoms can be ignored for years if you only drive locally and gently and not in hot weather...

 

How many miles on it?

Did it specify which cylinder? Last digit in P030X indicates cylinder number; for example P0301 is cylinder one.

What work specifically?

Thread title could be more succinct? Would you mind if I reported, asked the mod's to revise to something like "Misfire and coolant loss, suspect head gasket failure".

 

Did you also clean the intake manifold? EGR Pipe? EGR Valve? I am curious to get the comprehensive list just so we can see if all this time spent cleaning stuff may or may not be the silver bullet to preventing problems.

 

Understand. But as I said: the mod's can.

Including the intake manifold EGR passages? And at what miles did you do this? What motivated you, just from what you've heard, or were there symptoms happening?

Also, could you answer these, from my previous post:

 

There is no silver bullet to preventing hg problems on these cars. It seems to be age related as well as miles since we are starting to see 100k mile hg fails when a few years ago it was 175k miles and above. We see plenty of clean free flowing egr systems with a hg fail. Certainly cleaning and replacing misfire related parts will not fix a failed hg.

In this case the op should take it to Hybrid Pit for an early diagnosis and recommendations. Waiting just guarantees a higher bill later on. I always suggest a rebuilt engine, ideally one the never experienced an overheat or hg issue. A rebuilt engine includes pistons and rings.

 

Where some of these clean EGR’s done on the heels of head gasket failure symptoms starting.

@ASRDogman is a canary in the coal mine who’s on orig head gasket, closing in on 400k miles IIRC, and proactively cleaning the EGR.

 

At what miles was the EGR done? 153K?

 

Ok, good to know, that's timely.

 

Thanks for this information and good summary on your theory as to why head gasgets are failing. I appreciate your take on things.

Do you have a theory as to why yours failed even though the EGR system was never pluged?

You state that the "car was run in very high temperatures for several days in Palm Springs" but I dont know if high ambient temperatures would have that much of an effect on things?

 

That story leaves out something absolutely fundamental about the Atkinson cycle. What makes it the Atkinson cycle is that the compression ratio and expansion ratio are different.

The Prius engine has a 13:1 expansion ratio. It does not have anywhere near that as a compression ratio, and such comparisons to diesel engine conditions are off the mark.

 

Theory? Wait til you read the 200 something page about adding a occ first.