Engine knocking, CEL, fouled plug, and lost coolant

Option B
Replace just head gasket....
Check for scars on cylinder that was in contact with coolant...
Remove and inspect piston ..rod ...rings.....and bearings.....inspect head valves....
If all are under specifications
Head gasket will be worth
All this is considered if you do yourself....labor involved to do this will be almost 50% more than just replacing entire engine

 

The engine that gets pulled out likely gets rebuilt, eventually ends up being dropped into someone else's vehicle I guess?

 

Damaged engine are a lot cheaper.....get solid short block assembly.....and re-use head.. . with blown head gasket i will check for warped head and do pressure test for cracks ...
Also you can pressure test valve assembly and inspect guides and seals on valves

 

Once you dig engine out it is easy to inspect and see best solution.. .....

 

I have very little doubt that the electric water pumps on probably a majority of reported Gen 3 head gasket failures have impellers that aren't doing much of anything. The problem with this electric set-up vs. a mechanical water pump is that there is no bearing squawk or coolant getting flung around the engine bay to hint at an impending failure. I don't know if the Gen 3 has a code for the engine water pump but I haven't heard anyone reporting so, only the overheat light, at which point...

Thanks for checking in, we need data on this issue. I've purchased the Aisin pump ($260 on eBay) and will be swapping mine out preemptively as soon as the northeast comes out of the meat locker. My 2010 just turned 136k miles.

 

Here's water pump replacement instruction from Repair Manual:

 

Sammy, I think I would be looking for a good used engine. Based on the multiple issues you have had it seems like it would be the best option to cure all. Looking for a 2011 engine might be a good option to make sure you do not incur ring issues with the replacement. It is sad as others have said that the Gen3 seems to be having more mechanical issues than older generations. I have heard from friends at Toyota and Lexus that the issues you have going are not extremely common, but still there. I agree with your timeline that you most likely have the 1 piece oil control rings in your engine that are responsible for oil usage. Repair of this would require replacement of the pistons with the updated design. The head gaskets are also prone to failure that typically starts with a misfire when started with small amounts of coolant being ingested, and progresses from there. I have not heard of failures of the electric coolant pump, but in your case it sounds like there is a problem with the pump or the thermostat. This issue most likely accelerated failure of the head gasket. I am contemplating replacing my pump, but that's a tough call.
I purchased a complete engine and transaxle that is sitting idly by in my shop for when its needed, or for parts. My hope it is gets to stay there until at least 300K miles.

 

Awesome, Mendel, thanks. Filed in the ill-gotten folder.

 

Since there are two coolant loops, are there two water pumps?

 

You just gave me some insight into increasing the scope of the 200k mile service I was planning.

Currently at 149 k, so I have a little time, but I agree that a little preventative maintenance may go a long way on this issue.

When you do change the pump out, I for one will be curious in what you find. Keep us posted.

 

Yes, here is the inverter loop pump for your PiP:

2012 Toyota Prius Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping

This pump appears to be a strong point with regard to Gen3, as failure reports are scarce to non-existent around here and the car will absolutely throw up P0A93 if an issue is detected. With Gen 2 it's a different story, and was subject to the famous C0U recall. One thing I've observed of note is that when observing flow movement in the inverter reservoirs of both Gens 2 and 3, the 2 is observed as "turbulent" and the 3 is a more gentle, "flow" type of movement. No idea if there is a difference in pump pressure between them, just an observation. Movement in the Gen 2 bottle is a bit more aggressive than in Gen 3.

 

I will document this project and attempt to video running both pumps (old and new) via Techstream, ala the Luscious video I've posted around here. I'm challenged with regard to modern electronics, thus the video "attempt" noted... Of possibly particular interest to you, I will simultaneously be replacing the EGR valve/cooler with an incredibly mint 20k miles, 2015 salvage I snagged on eBay for $115 shipped! Intake manifold de-sludge will be performed despite it being done previously at 100k. I have gaskets for the entire circuit plus t-stat for the engine loop. After this, I'm gonna try and not fret potential head gasket issue and continue hammering this car for many years.

 

Sounds like a good list!

The t-stat I have thought about doing as well. Easy to access with the windshield cowling off and coolant drained. Maybe I'll add that to the 200 k miles servicing plan.

Pretty good deal on the cooler and valve. I picked mine up from the local salvage yard for $100 a couple of years ago. The upper support was bent, so I had to JB weld it back on. When you remove the cooler, you'll see why. Looks like yours is missing one of the exhaust manifold studs, maybe that's how they got yours out.

I would recommend trimming the lower support for the cooler to avoid fitment issues when going replacing. The 2 studs for the exhaust manifold and the one on the block for cooler support make it challenging otherwise.

I have my own technology challenges. I had a flip phone until last year at Father's Day. My philosophy was if it ain't broke, keep using it, but the wife had other ideas.

 

I'm wondering if the head is flexing from excess heat if a new waterpump could cure your problem and reseat the head? Or maybe the engine is permanently damaged.

Makes sense. I'm planning on changing it around 100k miles. Does the pump output fade over time or does it just suddenly quit?

Good to know Toyota fixed the oil control ring in 2011.

 

Let's do it end of next month.

 

Unfortunately I am at 149 k miles, but maybe next time for an engine coolant drain, windshield wiper cowling removal, egr system removal and spark plug changeout. If I am taking the cowling off, I am going big!!!!

And if I am doing all that work, I might want to execute at my place, as there are opportunities for things to take long and take an additional day. But I can host the meet up.

I'll bring my spare valve and cooler if you want to investigate your system when we meet next month.

How many spots you got filled for the end of march meet up ? Got any open spots yet?