Any Gen 4 Owners Out There With Blown Head Gasket ??

Yep, coolant becomes acidic over time which is one reason to drain and fill every 5-years (or 100,000 miles) whichever comes soonest. The acid will start eating up the head gasket. (But Toyota has improved the quality of their head gaskets which was a much bigger issue in earlier models.) Excessive heat and acid will ruin any head gasket.

Last year, my wife's 2017 was due even though it only had 28,681 miles and took less then 2 Gallons of Toyota coolant for both the cooling system and traction battery coolant.

 

Yep! A very important reason to read the foot notes in the maintenance schedule and insure the coolant is being tested as required.

 

My local Toyota garage contacted toyota GB to ask for the car to be fixed under warranty. They refused saying it is part of the exhaust and is not under warranty. They are having a look at my car tomorrow and will try and bypass the problem part, as others seem to have done.

 

Keep that in mind next time you're car shopping.

The heat exchanger is a common fail point on 4th gen, they know, and still shirk their responsibility. Penny wise and pound foolish.

 

You personally need to take it up by email with Toyota UK in Surrey otherwise you won’t get anywhere. You’ll need to put together a case and there’s lots of supporting information on this forum. At the moment your local garage has likely made a quick enquiry and been told “it’s not covered” without any further investigation.

 

Sounds like dealing with the Wizard of Oz...

 

Maybe you should contact @The Professor as he is in the UK and is getting his replaced under warranty, but is still having to pay for labour and ancillary items I believe.

They have done the bypass whilst they wait for the part to come into stock.

 

That’s at least more pragmatic than North American dealships who refuse, citing “pollution control compromises”.

 

I think I might be having this issue my 2016 popped a P0117 and started to over heat and I lost all the coolant thinking it’s the heater exchange ? Could I be right ? Can you really bypass this ?

My 2016! Is having this issue

 

Yep and one of the many reasons it's important for us to KNOW our cars...regularly pop that hood and check all fluid levels and keep an eye underneath the car for anything leaking. While it's normal to get water underneath the car from the air conditioning, take a look at it to make sure you don't see any pink/reddish color, which is coolant. Nothing will fry the head gasket faster than an overheating car which is why I've told my girls to pull over and shut the car off if they ever get the coolant light. (Yes, it might just mean the reservoir is low but it's not worth the risk.)
In the Prius', when doing oil changes, I'll shine the line down the muffler and see if there's anything leaking or anything pink/reddish around that heat exchanger....so far, we've been good.

 

That's why there is no longer an exhaust preheater on the Gen 5 Prius.

 

And subsequent reduction in mpg’s?

 

Also, less headaches and less wallet lightning cost to the owners and costs of replacements for Toyota.

 

One of the few things that worked fine on the gen 3

 

Yeah either 4th gen design revision messed something up, or they had a manufacturer who did something poorly.

 

We’ve had quite a few complaints here, but many have had no trouble. Makes me think defect

 

Maybe a production batch, supplier change, or an American worker on the line

 

Well, think about it. The gen 4 exchanger is after the cat. The gasses are WAY hotter there then in the gen 3 location. Burn through isn't a big surprise to me.

 

Just need better materials?

 

Maybe that was to keep the (downstream of the Cat) EGR connection from getting even longer.