2018 Prius head gasket blown

You should call Toyota corporate (their toll free number) and ask for them to assist in the repair cost. There is no way a properly maintained car from Toyota should have this failure.

 

Is "they" a dealership?

Not that it matters much, dealerships have been misdiagnosing 4th gen coolant leaks in the exhaust heat recover system, as reported here quite regularly.

How did they diagnose the head gasket failure?

Was the possibility of coolant leak in the exhaust heat recovery system mentioned? It is much more prevalent, and there's a Technical Service Bulletin (or similar) on it.

There have been several reports of failed head gaskets in 4th gens here, and as far as I know, they all turned out to the exhaust heat recovery system.

Also, the replacement parts for the exhaust problem are largely unavailable. The workaround seems to be connecting the intake to outlet, bypassing the system. Dealerships are all refusing to do this; it's disabling a pollution control. So owners DIY or go to independents.

 

If compression tested good on all cylinders, most likely isn't a BHG. They need to put the car on a lift to look at the exhaust heat recovery system; it cannot be diagnosed with a cursory look at the engine bay.

 

I've read here that it's part of the emissions and the fix should be covered and performed under warranty.

 

Dealership's batting average not so good.

 

thank you toyota

 

I'd want to use the springy hose clamps though.

 

What’s the trick for sizing those? I got some, measured OD of hose, ordered that size, and that’s what the ID of clamp was, at rest. So just snug, next to no clamping action.

You want them with ID a mm or two smaller than hose OD. And that would be when pushed onto spigot or barb connector?

 

I don't rightly know. Online ordering makes it harder. I might walk into the local auto job shop with the hose and the barb in my hand and say "what springy hose clamp for this?"

Or look for a similar-sized hose used in the car, and pick up the Toyota part number called out for that.

 

How does a dealership not know this is the heat exchanger

 

It’s a dealership: does anymore need to be said?

 

They don't call them stealerships without good reason.