Head Gasket Bolt Failure

Technically, it's tough luck, but considering the nature of the failure, hopefully you can get Toyota to step up.

What have they said, so far?

 

Do a search on Camry 4 cylinder head bolt failures. No pretty but you'll also see some remedies if you don't want to pursue engine replacement.

 

We need a law against stealersips charging people $500 just to look around and not fix anything. I say triple damages for any criminal who charges that much and doesn't even fix anything!

 

Maybe a two-level rate: a bit cheaper for diagnostics? I can appreciate time is money, but paying without forseable resolution is frustrating.

 

It's called being an informed consumer and making a smart choice with your "feet." Simply, noting from the initial finding, an inexpensive compression test was needed, although there may have be a charge for removing the cowl to get to them.

My choice would be a complete new, used or rebuilt engine.

Head bolt failure can result from improperly forged or a bad batch of ally used to make them or improper torqueing and installation.

 

It's a free market and nobody is forcing anybody to pay this. If you're in the dealership in the first place, you should have one hand tightly clamped on your wallet.

 

In hardening of metals, such as the head bolts, metals exhibit a continuum between ductility and frangibility.

Ductility is whether the metal is soft enough to be drawn out or stretched. Hardened and quenched steels have a high percentage of martensite resulting in a state that is easily broken by shock, bending or stretching.

After hardening bolts of steel are tempered at a temperature of 250-450 degrees F over a period of time. This restores some ductility to the bolt which increase it's resistance to shock from temperature and pressure.

Bolts are like rubber bands, it that, when tightened, they are stretched. An improperly tempered bolt will crack under repeated stress.

Evidently, the bolts in the OP's engine were apparently improperly tempered.

 

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Or over torqued. Or had a pre-existing flaw (a crack or stress concentrator). Or improper material, etc. You can't tell without the failed bolt in hand for examination.

 

Well, not a Prius though, but have experienced this situation on a Camry 05. Was pretty much overheating and boiling water out.
Had to removed the bolts.
I still don't know what caused all that. About 5 bolts were not just tightening the top

 

You already are getting another engine. Y wasting that funds to investigate a bolt failure? Are you intent on using the old engi

 

Try the local university engineering research lab.

Steel alloys are like an aggregate of crystals of iron, carbon and other alloying elements that are "forged" and heat treated. That process caused the crystals to become very brittle. Tempering reduces some of the stress and "toughens" the

Hundreds of thousands, even millions of stress cycles of pressure and heating and cooling causes the bonds between the alloying crystals to separate. This cannot be predicted before the bolt is installed.

In aircraft applications, engines are required to be torn down and examined after a certain number of hours of operation. Metals parts are examined for stress cracks. For steel, Magnaflux is one method of finding stress cracks.Even then, they prematurely fail suddenly before the required rebuild.

 

Now I'm scared.

 

Neither the Charpy V-notch test or the "stretch" or tensile strength test can predict long term fastener failure. And, the bolt does not have to stressed to the elastic limit to eventually fail. Aluminum is more susceptible to low level repeated stress cycles than steel alloys due to vibration and change in pressurized cabins in aircraft. Like bending metal back and forth, the crystals begin to separate at the crystalline boundaries. It is commonly referred as metal fatigue.

 

I am looking at a 2013 Prius C to purchase. When reviewing the maintenance history available on the Toyota website I noticed the same issue as you, @Just Curious. It was at 78k miles. The details state: CYLINDER HEAD GASKET ~|~VEHICLE IS LEAKING COOLANT ~|~HEADGASKET LEAKING FOUND HEAD BOLT STREACHED REPLACE GASKET AND BOLTS.
It was repaired under the Toyota Care Warranty. I haven't purchased this car yet but wanted to share.

 

Sometimes being an informed consumer and making a choice with your feet isn't an option... When monopolies like Amazon & FB keep destroying the competition and aren't held in check with regulations, consumers get no vote. It's even worse when it comes to competition amongst internet and cable TV providers, once they establish a monopoly and are the only viable option, they can make life very expensive and being an informed consumer becomes irrelevant.

 

In the case of automobiles (as was described by the OP), there are other dealers and a plethora of independent mechanics who can do work for you. So, despite your concerns about the state of the free market in general, in this case it is quite easy to vote with the feet. In fact, that's what was done in this case.