2016 Blown Head Gasket 377k miles

are you sure it's the head gasket and not the exhaust gas heat exchanger? Don't know if the TSB will cover it with that kind of mileage on it.
the problem with the K-seal is that it plugs everything up. Possible no heater, or overheating next summer due to clogged radiator or heater coil.
I'd drive it for another year to make sure you don't have any cooling system issues before dropping more money into it.

good Luck....

 

Is the coolant level stable?

wonder: would k-seal work on the exhaust heat recovery system?

On Gen 4 there have been defects in the EHR system, allowing coolant to leak into the exhaust. One or both of the following may happen:

1. The coolant loss fools mechanics into a failed head gasket diagnosis.

2. Coolant loss carries on long enough that the engine is starved of coolant, and the head gasket DOES fail.

 

is it that unusual to blow a head gasket on a high mileage car?

 

How severe was coolant loss prior to that replacement? Could have overheated a few times, enough to degrade head gasket.

Which could arguably make it Toyota’s responsibility, since the coolant loss was due to their defective exhaust heat recovery system.

Still, their record for responsibility is abysmal of late. Something to keep in mind next time you’re car shopping.

 

boycott toyota? fair enough, but who ya gonna trust to get 350,000 miles out of?

 

Yeah meant to add, likely all manufacturers are in the same boat, cutting corners, ignoring complaints, rushing products to market with insufficient testing. With 3rd gen, both the EGR system and low-tension piston rings seem rushed to production, with (obviously in hindsight) insufficent testing, to gain a few tenths of a mpg brownie points ($'s), and leave the owners holding the bag.

I think all you can do is preserve the car you've got, learn it's foibles, and keep your ear to the ground, for one of the manufacturers to maybe wake up, make an effort to be responsible.

When you're driving less than 5k kms yearly, garage-stored, and hanging out here half your day, that's not that hard.

 

If I got 377,000 miles out of a car before the engine wore out, I'd be very happy. I have zero intention to keep a car that long.

 

i only got 87k out of mine. now that is cause for complaint.

 

Its becoming more apparent that age is as much of a factor with hg fails as miles. At one point we never saw a hg fail with less than 150k miles. Now 125k is common and the outliers are less than 100k. It gives some credence to aging coolant as one of the important factors. Toyota Europe thinks it is thermal cycling (which causes hotspots as the engine cools off quickly) during long idles and stop and go. I am waiting for the day Mendel's hg goes.

 

Me too, EGR cleaning is getting mundane.

 

i never changed or checked my coolant, so a possibility. it was never a problem with other cars, although our windstar blew around 90k, a known issue.