Head Gasket Replacement Shop Recommendations- San Francisco Bay Area

I've been watching the Gen 3 Head Gasket replacement videos by Gasket Masters and NutsAboutBoltz. Initially, I was gung-ho about taking this project on. But now I want to look into what it might cost if done by a reputable SF Bay Area mechanic or shop. I'd like to hear from any fellow SF Bay Area PriusChat members who have had this work done by someone they would recommend. Has anyone in the area had Gasket Masters replace their head gasket? Other mechanic or shop?

I don't see people here usually saying how much they pay for service, etc. Maybe it is frowned upon? If It is OK to share cost info via private message via this site, that would be good to. If anyone has recommendations for a person or shop in the area, I could call for an estimate as well. I'm probably not willing to pay dealership prices, but I would be curious of that scary price tag.
Thanks in advance.
Dave

 

Thanks for the ballpark costs of the different options! I am still in the diagnostics phase, but so far head gasket seems likely. The EGR system has never been cleaned. I will be calling Gasket Masters for estimates for head gasket replacement and for a JDM Gen 3 and Gen 4 into Gen 3 Conversion into my 2013 Plug-in. Am I correct to assume my 2013 Gen 3 Plug-In's engine would be exactly the same as the non plug-ins, correct? Initial research seems to say a Gen 4 Engine can be swapped into a Gen 3 with some minor modifications (one being to put my Gen 3's EGR onto the Gen 4 engine). I do wonder if it would be all around easier for a DIY'er to do the JDM engine swap vs. the head gasket procedure. Assuming I rented or borrowed an engine hoist.

 

Have you used this shop personally, or know of others who have for HG or JDM engine swaps and their reliability? I'll check them out.

 

Never. /

I don't know over what period of time the Engine coolant level had dropped well below the minimum mark. It's my wife's daily driver, so I'm rarely under the hood to notice. I changed the oil in Sept of 2025. It's likely I would have noticed if the coolant reservoir was down much from the full mark at that time. After my wife first reported a check engine light 1/28/26, I saw that the coolant was WAY below the Min. mark, but still showing in the reservoir. Without running the engine, it took 1/2 gallon of 50/50 Zerex coolant to bring it to the full mark. It has remained there to date, but it has mostly been parked except one three mile errand after the coolant was added and the codes were cleared, thinking the issue would be solved by adding back the ≈ 25% of the missing coolant.

On her next, same 3 mile one-way errand, she got the shaking engine again. NOT from cold-start, but AFTER her short 5-10 min stop at the shopping center. She had one more (3rd) trip to that shopping center, with the same result of the jerking engine just after she started back to home. Tonight, I made that same trip, which was MY first time for a first-hand experience. It drove smooth as normal from cold-start on the 3 mile trip there. I was continuing my research, parked, and go figure two hours went by. ;o) When I put the car in Ready, it ran on the battery until I got onto the highway. As soon as I accelerated normally, it switched from HV battery to the engine, and immediately there was ≈ 2 seconds of engine shaking, then smooth again. As I continued this test drive, stopping several times for varying amounts of time (2, 5, 10 mins., every time the car switched to the ICE engine, the ICE rattled for 2-3 seconds, then smooth again. I had my Autel MK808S scanner in 'Live Mode' to monitor the ICE while I drove. Outside ambient temp. was ≈ 50ºF (10ºC). On my 3 mile drive out, the coolant temp was 158ºF (70ºC). On the return trip, the temp started rising 170, 185. So, as I was now in a 25 mph (40kph) zone, I slowed and accelerated strongly several times to see if it would continue to rise. It got up to 195ºF (90ºC). Hmmn? Then I continued driving, but normally, w/o the hard accelerations, and it settled at 170ºF (77ºC). I took it back out to the highway to see what a steady 65 mph (105kph) would get for temp. At that highway speed the coolant temp was a steady 195ºF (90ºC). Hmmn?

Would you agree that it seems to be a hot-soak restart misfire, not a cold start Misfire?
What does having a hot-soak restart misfire, instead of a cold start Misfire mean?

No, see above.

TLDR: I don't think it has used oil, at least in the ≈5 months, ≈5,615 miles (3,500km). But if it has, then ≈1/4 quart since changed.
As I mentioned, I changed the oil just under 5 months ago (9/9/25 @ 208,395 miles). When I checked the oil when the issue was first mentioned (1/28/26 @ 214,008mi), the level on the dipstick was 3/4 the way up from the bottom dot, 1/4 way down from the top dot. "Ok, 1/4 quart* low, let me add some oil". But I had NO 0w-20 oil on hand, weird. I don't 'remember', but that made me think, I must have put in all I had, and made it slightly short of full, and said "fine for now". The oil was golden and clear, zero milkiness, certainly no foaminess. So maybe no coolant is seeping past the piston rings in Cyl. 1. It is driven most days, often more than once. Maybe the amount of coolant that seeps into Cyl. 1, in say 15-20 hour driving gaps, is not enough to 'seep' past the rings??
*Most of my experience is with vehicles that hold between 4.5 to 6 US quarts. I have always assumed, maybe incorrectly, that the amount between the low 'add' mark and the top 'full' mark was one quart.

 

Well, thank you very much for the enlightenment that a Gen 4 to Gen 3 car conversion is NOT a slam dunk. That saves me a day of chasing down a rabbit hole!! For a minute there, I was loving the idea of having a 2022! Gen 4 ICE in our old(er) girl. I hope there are still plenty of '13, '14 and '15 Gen 3 JDM's on the market. As I typed '15, I vaguely recall seeing something about the 2015 Gen 3 ICE being 'different' than the 2010 to 2014's. Is a 2015 Gen 3 ICE off the table as an option?
@rjparker , I really appreciate your sharing your very specific knowledge! Cheers, Sir.

 

@rjparker , I think +/- $3,000 to get Gasket Masters to do an engine swap sounds very appealing. The evidence so far is pointing strongly to a coolant leak into Cyl. 1. But before I start calling to ask Gasket Masters for a quote to an engine swap, I want to find a good borescope to buy, then pull the plugs to inspect the cylinders. I like the idea of a borescope with an articulating head. Not sure if that would let you see 'up' to look at the top rim of the cylinder. But that may not reveal anything visually telling/ useful. Initially, I thought you'd be looking thru the spark plug hole for a silver (steam cleaned) Cyl. 1 piston. But from NutzAboutBoltz's Part 2 Head Gasket Replacement video @ 28:24, Cyl. 1's piston is just as dark as Cyl. 4. BUT Cyl. 1's piston is WET. So, my plan is to buy the borescope, Day one, remove wipers, cowling, etc. to have access to the plugs. Drive it to get it to operating temp. How long should I wait to remove the Cyl. 1 plug to check for coolant with the borescope? As I recall my test drives last night, starting to dive after just a short 5 min. engine shut off, got one second of engine shake. So I guess my answer is not long! Would the heat-soak coolant seep rate (or make it stop?) change by removing Cyl. 1's plug, say 5 mins after stopping the ICE? Hmmn, maybe pulling the plug would increase (15 psi pressurized) coolant's flow into the cyl.? Not sure if an intake or exh. valve happened to be open, if the Cyl. similarly allow free flow of pressurized cool, the same as with plug removed.

Anyway, next step is to decide on a decent borescope, then continue.

 

Well THAT is good to know!
I always say, "If you are going to make a generalization, you might as well make it Glaring!" ;o)
The owner's manual says the engine oil level is 'Low' as it lowers to the bottom mark. That means that the ICE has ≈ 2.8 US quarts (4.4-1.6) circulating, and that is adequate/ fine for normal operation. Wow, the oil level can drop 36% (1.6 Qrts) and still be within spec.. Interesting.

Another bad assumption on my part. I thought maybe some coolant could seep past the piston rings, being much less viscous than oil. But I guess the compression and oil rings do a good job keeping that from happening.

Now, knowing my Prius' issue is not a cold-start leak, but a heat-soak leak. If I understand correctly, this means a smaller, earlier HG failure leak, correct? That being the case, I wonder if it is worth considering using Bar's Leaks Block Seal Head Gasket Sealant, to kick the can down the road before an eventual JDM engine swap. In a ChrisFix video Do Head Gasket Sealers Actually Work, he adds 'Bar's Leaks HG-1 Head Seal Blown Head Gasket Repair' (diff. version than above link) to his dad's older Jaguar that has a bad head gasket leak. He tests it for 10,000 miles, two years, before the issue returned. In the video, he cut the tanks off the radiator to reveal that the cross tubes in the radiator were clear, not blocked (he also tore down the engine). I have no idea if the Prius' coolant system might have smaller pathways that would be more prone to clogging than that older Jag.
Just a thought...

 

I understand that driving it in its current condition is high risk for the reasons you mention. We are keeping it parked.
Is your point that investing $5k (to get an engine replacement) is not worth putting into a 13 year old Prius? I've been wondering what $ amount "IS" worth putting into this old of a Prius Plug-In? $5k certainly would be a stretch to spend on it, but $3k- $3.5K feels in the realm of more OK. But deciding not to repair it, not sure what to do with it. Not sure what $5k would buy, if one was strictly looking to compare repair vs. buy a replacement used car with similar gas mileage. Not really looking to write it off and just go buy another similar Prius, say coming off a three-year lease. That would not be my first choice at the moment. Maybe an unpleasant (costly) choice will be prudent, IDK.