Blown head gasket, should I swap engines or... ?

We have a 2013 Prius V with 130k miles, it's been our primary daily driver since we bought it in 2021 with 90k. It's the perfect car for our needs, and I had planned to keep it another five years and 80k miles or so while we save for a replacement. Several months ago I got the dreaded P0301 misfire with occasional knocking on cold startup, and did a bunch of maintenance work in hopes that I could stave off the head gasket failure: fully cleaned the intake manifold, EGR system, fuel injectors, changed spark plugs, labeled and swapped locations on ignition coils, replaced the PCV valve and installed an oil catch can, drained coolant and replaced with new. It ran great after that, no knocking, the code cleared after a few days of driving, and we put around 4k miles on it over the last two months. More details are in a post I made about three weeks ago:
P0301 misfire, dealer says blown head gasket - options? | PriusChat

But of course, it WAS a blown head gasket, and the code and knock returned. The dealer and a local independent shop both tested the coolant and found "lots" of hydrocarbons in it. We didn't drive it after the code came on (both times) except driving home and then to the mechanics for the diagnosis.

The dealer quoted $7,800 for an engine swap with one that has 90k miles, since they don't change head gaskets on these cars - they say it's too likely the head is warped. The independent shop quoted $5,670 to do the head gasket (including resurfacing by a machine shop), which they would remove the engine to do. I declined both, since the car's KBB value is around $9,500 in the "very good" condition it was in before the head gasket blew - it doesn't make sense to put that kind of money into a car of this age and value.

It looks like LKQ has many options for JDM motors available a few hours' drive north or south of here, most are around 40k miles and $1,200 (plus shipping). I'm inclined to take that option and do the engine swap myself; I would need an engine hoist and maybe a specialty tool or two, but I have a pretty good set of tools and enough experience to have confidence that I can do it properly, and I can make time for the work.

The other option I'm considering is replacing the head gasket myself, which would certainly be cheaper but I have less confidence in that job. I did that on a 92 Subaru many years ago when a friend worked as a mechanic and gave me the use of a bay for a week, tools, and advice as I went. I have none of that now, but I do have a clean, dry, well-lit garage and can probably do it. I'm hesitant about that, it seems more likely to fail later on, and I don't have any mechanic friends nearby to help seat the FIPG on the timing chain cover (which is already leaking, so slowly I don't notice oil level dropping on the dipstick). An engine swap by comparison is "just" unplugging everything, pulling it off the transaxle, then hooking up everything to the new engine.

We've talked about replacing the whole car instead, but if we do I'd want another Prius V, a few years younger and under 100k. After selling our current one for whatever we can get for it with a blown head gasket, that would cost us around $8,000, and seems just as likely to need expensive repairs in the 8 years I'd want to keep it. Also, we have a set of winter tires on wheels for it and the brake booster replaced about 8 months ago, so it seems like once that and the head gasket are done, this car would have the two typical expensive repairs done and shouldn't have major issues in the next 5 years. AFAIK, the hybrid battery and inverter failures are less common and less expensive - is that true?

I've read some threads here about swapping in a Gen 4 2ZR engine to this Gen 3, to take advantage of the changes made that should be more reliable, and there are plenty of those available for similar cost from LKQ. I know in 2014-15 there were some changes to pistons and rings, and later (2018?) was a bigger change for Gen 4, the black plastic valve cover is an indicator. Do the Gen 4 engines pull the EGR from after the catalytic converter? Are there other changes that make the head gasket failure less likely? If I'm going to swap the engine anyway, it seems worthwhile to get one without these known issues, especially if we could hope to keep it another 8 years instead of 5.

We have an old, high mileage, gas guzzling Honda Pilot as our second car that we're sharing until we have a good primary car again, and I have more time than money to throw at this problem. Is there a better option that I'm missing? Spending under $2k for an engine swap is about the most cash our budget can handle; a replacement car would require a car loan, whereas we paid off this one a year ago. I don't like any of the options I know of - do you have any ideas?

 

If there was any misleading, I did it to myself. I could have gotten a coolant test or whatever, but I chose to "do my own research" by reading dozens of long threads here, and chose to hope that a simple misfire was caused by not having done the 90k and 120k maintenance work which could possibly cause that, so I did that plus the EGR and intake cleaning. In hindsight you're right, I should have done more diagnostics and saved my time, but the outcome is the same either way.

I'm awfully tempted by a rebuilt engine that could theoretically take me another 200k miles, but what about the rest of the car? We had the brake booster work done recently, but there's the hybrid battery and the inverter, not to mention all the usual little things that fall apart with age. I spent almost half my adult life dirt poor and driving/fixing old cars that others had given up on, and have never owned one younger than 8 years or less than 90k miles, so I'm hesitant to put a perfect engine into an aging car. Your signature shows you have our past car (Gen 2 Prius) and our current car (Gen 3 Prius V) plus our future car (Gen 4 Rav4 hybrid) so I wonder about your 2012 V with well over 300k on it now - is little stuff breaking? Does it have the original engine, transaxle, hybrid battery, inverter, etc? Have you replaced suspension components or other mid-expense wear parts? Is it a daily driver, and how long do you plan to keep it? (Tell me, ghost of Christmas future...)

Right, this is why I don't want to do the HG work myself. I can pull a rabbit out of my hat in some areas, but not here. I would trust my local shop to do a good job, but the $5,670 they want doesn't seem worth it when I could swap in a perfect engine from Hybrid Pit for much less.

Thanks, this is super helpful! I know it's hard to verify much about used engines for sale, but Japanese regulations are obvious and a true JDM motor should have around 40k miles - this info helps me sort through the listings on LKQ.

The nearest big cities are Portland and Sacramento, so I'll probably pay for shipping regardless, but do you have any links? Or even the right search phrase? I can drive my Pilot and utility trailer to pick up something if it's cheaper than shipping.

Thanks again, super helpful! I've gathered much of this kind of info by lurking here off and on for years, but it's good to see it spelled out clearly. I wondered if this could be easy enough and a real improvement, but figured not - thanks for the confirmation.

 

I read your whole thread a few days ago, and got lots of helpful info, thanks for that and for chiming in here!

I may be beyond that option; their Manteca location is the closest to me but over 350 miles away, and I don't trust the car to get there safely. All told, we've driven over 4,000 miles since the first time the CEL came on for the misfire, although we drove it less than 100 miles with the CEL on (both times). Driving there for them to do the HG job is totally an option for me, but I'd want to be real sure that it won't be damaged beyond a simple HG when it arrives. How much did they charge, and was it really done without the car spending a night in the shop?

Right, I know I'm out of warranty on that - just like the brake booster that we paid over $4k to have replaced a few months after it was out of the TSB program to replace those, and a few months before the HG failure. It's been a lot lately and I'm tempted to hate this car and hate Toyota, but I've had too many old cars to react when something fails, and I won't argue with the near-consensus of auto industry insiders that Toyotas are among the most reliable cars available. Also, I'm pretty handy with electronics and have replaced the 18650 lithium cells in my power tool batteries, built my own audio amp, fixed my HVAC fan after the tech misdiagnosed it, rewired the well pump so it wouldn't burn the switches after the installer did it wrong, etc - so I'm inclined to cross the hybrid battery bridge when I get there with DIY cell testing and replacement. That's another thread, but while we're here, does anyone have experience with DIY battery maintenance after getting the P0A80 code?

 

Yeah, we had that done a few months before the first CEL for the misfire. It was just past the TSB for extended warranty service for that one - I knew that but pressed the dealer to call corporate before spending the money. At the time I blanched at dropping $4k on this car, but had no other options to keep it, I can't get the part and do the work myself. Also I figured that should be the last of the "money pit" problems...

 

I've seen you put that in so many posts that I thought you had it permanently in your clipboard to paste in!