durability of replaced headgasket?

My 2010 prius has a blown headgasket at just under 130,000 miles. The shop wants $2,000+ to replace the head gasket which I would readily pay if I thought it would be a permanent fix. But from searching around I'm seeing how common it is on the 1.8L and I have to wonder what is to prevent this from happening again.

I had only owned the car 1 month and it was running fine averaging 50+ until one cold & wet morning it had a terrible knock/rattle when I first started (which I see now is also common). The knock cleared up right away, but that week the mpg went down to ~45. The following week the cold start knock/rattle returned and began to happen every time the engine started (including whenever it switched from electric to gasoline). That weekend I went to clean the manifold & egr and discovered the coolant level had dropped and eventually narrowed it down to the head gasket.

So, should I just dump the car as a mechanic special? Fix and sell? Or can these gen3s be reliable? All my other Toyotas have been good for 200-400,000 miles so I'm really disappointed in the prius...

 

Just updating this thread in case anyone in the future is searching for info on the potential reliability & operating costs of a used 2010 Prius

I went ahead and replaced the head gasket with Toyota's latest iteration (at that time, no idea if they've redesigned it again) and the engine is still getting 50+mpg & going strong 4 years later at 190,000 miles.

So in about 4 years & 60,000 miles my used 2010 prius has needed:

headgasket replacement @ 128,000 miles ($2050 including new plugs & cleaned manifold/egr)
EGR replacement @ 135,000 miles ($0 under California's extended emissions warranty)
Hybrid battery replacement @ ~155,000 miles ($2200 for new Chinese cells)
Hybrid battery replacement @ ~ 180,000 miles ($200 labor, battery was covered under 5 year warranty)

More normal maintenance:
13 oil changes (every 5,000) $70/ea =$910
1 set of tires @ 155K $350
1 12V battery replacement @ ~185K miles $160
5 sets Sylvania H11 bulbs (they only last 160 hours!) @ $30 = $150
Toyota hatch struts @ 190K miles $75
6 wiper blades (all 3 every 2 years) ~$10/ea = $60
1 set front sway bar end links: $45
HVAC blower motor: $45
1 set "beamtech" LED H11 bulbs @ $40
2 engine air filters @ ~$10/ea = $20
2 cabin air filters @ ~$10/ea = $20
1 set of LED parking light bulbs @ $10

I've averaged 51.4 mpg driving economically but without doing any crazy hypermiling pulse & glide type stuff. Gas here has averaged $3.78 over the last 4 years (currently sitting around $5). $4575

Fixed costs:
Registration: $160 x 4 years = $640
Liability insurance: $460 x 4 years = $1840
Biennial Smog Checks: 2 x $75 = $150
Depreciation: $0 !!! (bought it for $7,000 in late 2017 and its current market value is still around $7,000).


Close to total ownership costs (missing random car wash supplies): ~$13,550
Mileage driven: ~62,000

Total cost per mile: $0.22

So while I've been fairly disappointed in the overall reliability of this particular Prius (sample size of 1), its overall operating costs have still be very low and everything except the factory cd player/changer still works fine.

 

My normal prius/hybrid-specialty shop diagnosed the failure & wanted $1600 for a reconditioned battery with a 1 year warranty or $3000 for a new battery with a 3-year warranty. I found a place nearby selling new (Chinese) packs for $2000 with a 5-year warranty, by my shop (which had already pulled my bad battery) told me they had too many packs from this company fail and they (my shop) would not honor that battery company's warranty. I got it anyway.

So when I got the triangle warning lights 18 months later, I just drove straight to the battery company who scanned the codes and said "yep it failed" and "yep it happens sometimes" - then charged me $200 labor since they didn't install the first one. They'll cover labor if it fails again within the original 5 years.

Its about $10 more than a semi-synthetic change from iffy lube, but it is performed by a prius/hybrid specialist shop and they use Amsoil, rotate tires, & even clean my egr every 10th oil change.

With two $2000+ repairs in the first 2 years I wouldn't say mine was reliable, but it has been economical nonetheless and should continue to be so in the future (even if it continues needing $2k repairs every couple of years). Insurance, registration, & depreciation are all pretty low on an old prius which, combined with 50+mpg, leaves a lot of room for repairs...

And to be fair, I think the previous owner dumped stop-leak in to hide its blown head gasket when selling it to me plus the battery probably would have lasted longer parked in a garage somewhere that didn't combine 100-120° summer highs with hills long enough to charge it to 100%.

Still, I put 100-350k each on an MR2, Tundra, and two Camrys - and none of them ever had the head off. In fact I think the only $500+ job was a clutch replacement in the mr2 and that was only because I was autocrossing it most weekends.