Considering Head gasket replacement - 2011 Prius - 215k miles - P0303 misfire

I did come a cross that video and its a really good video. I did double check all my hoses, everything seemed to be fine, which is why I believe it may be the hybrid battery. I also read that if the Prius does not run for an extended period of time (mine - 3 months), it may cause the HV traction battery to fail.

*I have edited my previous post to include the following:
-The first time starting my car (normally, not in maintenance mode) - it seemed to run for about 20-30 seconds or so then died.
-Then I tried running in maintenance mode. It would run for about 10 seconds then stop. It did the same thing a couple more times when attempting to put the car in maintenance mode. Now, after several tries, it won't even run in maintenance mode, it shuts right off.

 

Okay so I am dumb and the solution was related to the video. My intake manifold was not bolted in all the way and I forgot to reconnect the PCV hose.

Currently no check engine lights or hybrid system lights.

My next question:

-My exhaust pipe in the back of my car is blowing a pretty steady amount of a white smoke, almost steam like. I have let my car run for about ten minutes, the amount of white smoke seemed to decrease, but still seems pretty steady.

-How normal is this? If it resolves it self, how long of would it take? (Hours, Days, Miles?)

-I am currently at about a 20% coolant to 80% water ratio for my coolant (I do plan on putting in new coolant). Can this be related to my coolant being mostly water?

*On colder start, white smoke did not appear right away. After the car has been running for a few minutes, this is where I am at.

 

-I will have to keep an eye on it, but the reservoir does not appear to be dropping.

-After quick research, as you stated, could mean a warped head or maybe I did not torque the head bolts evenly. My head did not appear warped and I did a DIY slight shaving with 120 grit and 220 grit sandpaper (about 5 minutes with each grit of sandpaper). I am an amateur so it would not surprise me if I did something wrong, but I did try to be as diligent as possible.

-I am hoping it is coolant trapped in the exhaust or something but I wasn't having the white smoke symptom to begin with. Coolant is mostly water at the moment (80% water , 20% coolant, maybe even more.) Clear, water looking liquid seems to be dripping from exhaust pipe.

-When engine is cold, no smoke appears and it gradually increase to amount in the video after about 4-5 minutes.

-Engine feels hot to touch, so does the coolant reservoir. The longest I have run at one particular test was about 30 minutes.

 

In retrospect, I should have taken the head to a machine shop. I did use a straight edge and feeler gauge, it seemed okay, but this was my first time ever doing something like this.

I followed the sequence of 36 foot lbs, 90 degrees, 45 degrees. I went from inside out in an X pattern, as demonstrated in the Gasket Masters video. I marked each head bolt on a piece of paper and put a dash after each pass through. Its possible that I may have missed one head bolt at some point during one phase of the sequence, but unlikely.

 

Have mostly been using maintenance mode. In regular startup, sounds perfect, but seems to run mostly on Hybrid Battery/electric.

During Maintenance mode:
No startup rattle/shaking. Doesn't appear to be coolant reservoir loss. I have let idle for once 30 minutes and multiple times for about 10 minutes.

Yes, I wish I had a scanner, the one I used is very basic and only gives codes. No codes currently appearing or any warning lights for that matter.

Anyone have experience with these?

 

-I phrased it weird, I said I may have not torqued the head bolts evenly. I may have missed one pass or went over a head bolt an extra time, but those are the only errors I can think of.

-I stopped driving after about 500 miles from engine shaking and it only did this at low speeds. Based on this, I was hoping I didn't warp the head much. If anything, I am a bit worried I may have warped the head when shaving it with sandpaper. I was not initially getting the white smoke symptom at the start of all of this.

-I am concerned however because with maintenance mode the engine is continuously running and the exhaust smoke is still pretty consistent with the video I posted. I estimate my car has ran about 1 hour in maintenance mode total.

Tomorrow I plan on taking a desk drive, adding coolant and the Bars Leak/AC Delco coolant sealing tabs, seems like other people had luck using these.

 

Holding off on adding cooling system sealant tabs.

-Took about a 20 miles test drive today. Had my dad follow me in his car. During driving, he said there was very little of anything coming out of the exhaust pipe.

 

-Took one longer drive *60 miles with my dad following me for about 45 miles, when driving he didn't notice anything.
-A few minutes ago I put it back into maintenace mode and let run for about 10 to 15 minutes. Same thing as earlier, very gradual smoke at first and then smoke max's out to the video I posted and stays steady.
-Will have to keep an eye on the coolant in the coming days.

 

O-Ring Assortment Pack - 397 Piece Metric O-Ring Assortment

^ I wanted to post this O-Ring kit I used from Harbor Freight. It was a pain to find all the O-Rings when doing a head gasket. Also much more expensive if you order them individually. I called Gasket Masters and they suggested this kit. It's less than ten dollars and will give you about 60-70% of the O-Rings needs when doing a Gen 3 Head Gasket job. Plus you will have plenty left over.

I also wanted to thank everybody who contributed in this thread and for this board in general. The depth of knowledge Prius Chat users have is astonishing. I would not have been able to do this without this resource. I hope this thread will help somebody in the future.