Parts list [or thread referrals?]

I've owned my '12 plug-in for a year. 160k, 3rd owner Oil changes only, runs fantastic.
Correction: 'Ran' fantastic.
Symptoms, in order of apparent urgency:
A. Bucks between 0-25mph, fine above. Started a month ago mildly & sporadically. Increased in frequency and intensity past few days, now nearly undriveable. Seems to emanate from Left-Front.

B. Coolant Consumption: started in past week. I've performed 70+ Subaru head gasket replacements. I know these symptoms and don't need a coolant system pressure tester to diagnose this problem.

DTC'S, recorded & cleared, 100 miles without return:
0001 = Fuel Volume issue.
1145ish = Right Rear Speed Sensor. I have a full-size spare mounted, also 195/65 15 but diameter probably slightly off.

My thoughts, corrections most welcome:
- Head Gasket. Coolant not leaking to ground, & odor of cooking (glycol?) arriving in cabin. So, as failure has worsened could the bucking be caused by fouling plugs? I checked for LOW oil-level 100 miles ago; now I'll check for HIGH level. If high, 1000% confirmed head gasket (HG).
As the bucking was previously isolated to accel from 0-20mph I originally suspected that it was a problem within the hybrid drivetrain, but now that it is apparent at idle combined with the coolant loss I'm hoping the bucking is only HG-related. Frankly, that's a relief as I know my way around heads & blocks but know dyck about prius drivetrains. Still, no misfire DTC's seems odd...

Presuming HG, beyond Head Gasket/Oil Seals & Full Tune Kit any other Prius-specific parts-replacement suggestions?
- Water Pump/thermo?
- ........???
The absence of monitorable gauges is lamentable.

Many Thanks.

 

Question: are the cylinder head bolts reusable on this 1.8?

I'll fish for a torque-spec thread, as well as details on adding gauges (Thanks!).

Somewhat ironic that after I finish tweeking my Liberty CRD next month I was planning to sell the Prius. I am ethical, so the eventual buyer will be getting a 170k '12 plug-in with a decked head (& other Head work, if necessary), new HG/valve seats/etc., & cleaned egr components.
Head Gasket Set ordered @ NAPA, $160 (20%-off Sale thru Oct. 31th, but may be regional).

I prefer true rebuilds to unknown used engines so was also considering refreshing the short-block. However, the car still has plenty of power & no smoke whatsoever. Traditionally, Toy's are long-term bombproof when driven and maintained responsibly. Also, real-world resale there is a boundary of diminishing returns to consider beyond reparing known problems*.
Big resale plus: I just received the purple -and transferrable to buyer- CA. Carpool Stickers valid thru 2023.

As the Prius is currently my daily driver, I ventured a $36 chemical band-aid until I can pull the head. "Pour n Go" Head Gasket Sealer: Wow! This stuff actually works! I've used the overnight-set stuff a few times to transport Subarus, but this stuff you just pour into the radiator/intake hose & drive for an hour. Result? ZERO coolant loss & no more bucking!!! The Azone manager [credibly] declared he's been driving his own Accord for two-years on one treatment, including a 3k road trip.
I'm not sleazy & wouldn't sell a known-incorrect vehicle, but for a band-aid in a squeeze... cool stuff!

I'll post surgical updates.
Thanks for insights!

*Normally, during head surgery on my own vehicles I upgrade to ARP's. However, at +$200 not an instant choice for this soon-sold Prius.
Excepting its' anemic all-electric range, I *really* like this car: if I wasn't relocating I'd def keep it.

 

True, to an extent. By design, all of these seal-chems concentrate at points of pressurized leakage, therefore I don't share your opinion that it's automatically hazardous for normal-flow components or constrictions. Proof: I have rebuilt 3 Subaru 2.5's that I personally treated with sealant to facilitate delivery (of the other 60+ soob HG's I've performed, who knows how many owners did same prior?); all peripheral coolant system components appeared and functioned normally (although I typically replaced other coolant system components anyway, the culprit was poorly-designed faulty OEM head gaskets, '96-'04).
That said, the "set-overnight" stuff directs you to flush the coolant system after treatment. Though the "Pour n Go" stuff doesn't instruct flushing, your heads-up has prodded me to flush as a prophylactic measure. Thanks.

 

Also, I consider myself an ethical person, mechanic and seller. This Prius will have a new Head Gasket, etc., as required to make it run properly and reliably at the time of sale.

Re the azone manager's 2-year testimonial, who knows? They seemed genuine and their comportment passed the basic phony sales 'grin-and-shake' test. To quote, "My own car is proof, so if this stuff doesn't work for you call my cell and I'll personally direct any azone to refund your $36, no hassle."

As a seasoned soob wrench, coolant out the tailpipe -or in your oil- means ONLY one thing to me: HG.
[Well, at least way before warped/cracked steel...]

 

Clearly our experiences differ. I have never had to replace a radiator associated with an HG job, nor had any clients report elevated temps or radiator failure following an HG job. Nor have any mechanic friends reported such failure. Obviously, using chem seal is an "emergency" measure intended only to keep a vehicle driveable until the HG job is handled.

Also, I suspect that ambient temps impact any sealant's standing viscosity and the consequent potential for coolant-passage constriction (currently, nothing under 55f here).

Curious, I searched opinions on head gasket sealants. Combining my own/my clients/known mechanics experiences with observed online reports I have to conclude that you are exaggerating the associated risks to other cooling system components.
This stuff is NOT fix-a-flat, lol.

Still, as mentioned I am going to heed your concerns and flush the coolant system as recommended by other brands of HG sealant.
Seems prudent, even if unnecessary overkill.
If I see caked crud in passages when the head comes off I'll report it. If so, education for all... including myself.

You did concede that the risk of blockage may depend on the type of sealant used.
That speculation seems reasonable.

 

My own experience, other personally-known clients & associates' personal experiences, and searching others' experiences online.

Including yours. Your own horribly traumatic personal experiences with HG sealants ruining your life duly noted (laughing with, not at, you). Decent counsel; PournGo flushed as preventative measure. I haven't driven since flushing clean; I'll report whether coolant level sinks as before and/or if running hot.

Re HG chem-seal, I referred to "standing viscosity", as in a "cold" engine at rest. I'm less concerned with the spectre of possible systemwide compromise while at operating temp and flowing. It seems logical that if the stuff coagulates or congeals in a way that may compromise other coolant system components that it would happen while "standing" at cooler temps, not while flowing at operating temp.

Food for thought:
Re sealants, on a mechanics forum someone posted that in order to remedy various minor imperfections in the production process that auto manufacturers ritually introduce coolant system sealant after their vehicles come off the assembly line. Although unconfirmed, that sounds entirely plausible. Especially at GM

Cheers