Self proclaimed expert explains why Prius Headgasket Failures are normal, early, and inevitable

Does this applies to the blizzard white paint peeling and solar glass / moon roof plastic seal peeling?

 

Well, just started the video and immediately had to stop. That's simple. Replace steel bolts with Al bolts. Same thermal expansion, done. Porsche uses those 1 time use Al bolts all over the place because they use Mg parts and steel doesn't play well with Mg. Can we/anyone find an Al bolt manufacturer to make replacement bolts for us?

moto g(7) power ?

 

All I can find with google is Artificial Intelligence. You can reuse orig bolts if they meet spec. Or play it safe and replace with same?

 

The guy in the video, who looks like he's wearing a Toyota service uniform, claims the bolts' being steel expand and contract at different rates than the aluminum parts they mate together. That this causes compression and expansion of the HG and thus early failure. So my thought is swap in Aluminum bolts to match the thermal expansion rate. Seems almost too easy a solution....

moto g(7) power ?

 

When have these problems happened? 10 year old vehicle? Or 2 or 3?
If it's 10, not warranty. NOT good, but still not warranty.

That's why I never liked the fancy paint. Very hard to match.

 

@ASRDogman you could get a job in a minute, as a Toyota complaints department front man.

 

Maybe I’m ignorant, but if the expansion and contraction of the motor from it being a hybrid is causing the gasket to eventually fail, why isn’t that the case for all hybrids? Gen1 and gen2 never had these problems, same for the Camry hybrid or highlander, ect.

It just doesn’t make sense that it’s engine temperature related. Seems more to do with a less than ideal headgasket, and the EGR system.

it seems the engine should stay hot once it’s up to temperature, especially on older Toyota hybrids that didn’t run for long periods of time with the engine off.

I’m not a certified mechanic, so this is just a thought!

 

Second gens just soldier on, the miles pile up.

 

Given the redesign of the EGR system for the 4th gen it could certainly be that EGR was a big factor in the failures. That is by no means a smoking gun though.

Many Gen 3 cars reach serious mileage without popping headgaskets or cleaning EGR indicating there are various factors at work, despite what many here seem to what to think.

 

Any statistics on head gasket problems vs. year of manufacture (with comparable mileage, of course)? IOW, did any of the minor revisions to the Gen3 design fix (or at least mitigate) the head gasket problems?

 

I am seriously running 3 quarts of 10W 40 in the trani.......... been in there almost a year.

 

what asrdogman wants to say is let us know when your car catches on fire.

 

It would be nice if it did....

 

It's really no thicker then what used to be the norm for fwd final drive units. 75W-90 gear oil, or something like Redline MTL which is a little thinner was very common place. Honda used to spec 5W-30. If you look at the comparable viscosities of 75W-90 gear oil and 10W-40 motor oil they are not that much different. Questionable as to why someone would want to do it in a Prius but not as outlandish as it seems at first glance.

 

None that I'm aware of. That would be too easy and actual data would prevent people from screaming about the headgasket all the time. Knowing other variables like how the vehicle was driven are just as important to seeing a full [picture as well. All highway, hypermile, heaby throttle, short trips etc....

 

Can you get adequate tensile strength in an Al bolt of the same diameter? Or would this mean larger-diameter bolts and redrilling/tapping the block?

 

What miles is yours at, and have you done any cleaning, the EGR or intake?

 

Good points.

I couldn't say for certain I'm not a metallurgist, nor claim to being even close, but I would guess that they are weaker than steel of the same size, hence why the aluminum bike frames that started showing up looked bloated in comparison to Cro-Moly.

moto g(7) power ?

 

Bolt strength charts known to Mr. Google suggest an aluminum bolt has about a third the tensile strength of a Grade 8.

So we'd probably be looking at bolts bigger in diameter by at least a factor of √3. Those would be pretty fat.

What I was given to understand about that was that it wasn't just about raw strength, but another important difference between steel and aluminum, that steel has an identifiable fatigue limit and aluminum does not.



You can apply repeated cycling stresses to steel and as long as you've engineered them to be below where that graph goes horizontal, you can repeat them forever and it never gets closer to fatigue failure.

Aluminum has no such property, apparently; every flexure ever put on it, however small, uses up some amount of its fatigue life, bringing the day closer when it fails.

I also read somewhere that aluminum skins on aircraft are pretty religiously replaced after so many operating hours, for just that reason.

 

112k on a 2011. Cleaned the EGR and intake last month when it got plugs. They were dirty, but by no means plugged.