Add my name to the list here... violent shudder when accelerating, engine warning light, into the dealer to assess the light, code P0300, P0301, etc. which indicates cylinder misfire, diagnosis as issue with intake manifold and crack in head gasket, beaucoup bucks to repair, yadda, yadda...
How many people on this board reported the issue? At least 25+ by my count. That is just Lexus CT owners who found this board to see why and how this would happen to such a high-end brand car and maybe to complain, probably countless others who just paid for the repair and just moved on without digging into it. Then there are also probably a multitude of others who have an actual Prius with this same engine with the same issue, and I have good sources who have looked at Prius boards that confirm this.
I purchased a CT200 late last summer, and over the course of the last week found out that this problem was really a problem with how Toyota/Lexus is addressing the issue. They knew long before any one of you hit 100K miles that this failure was inevitable, yet they did nothing for the customer to avoid the major issues - a blown head gasket, or at worse: hydrolock, a bent cylinder or a cylinder through the block, complete engine destruction. Sure, they put out a TSB on the intake manifold, but never did anything proactive to help the customer avoid the major issue down the road. Look at the TSB --> L-SB-0019-16. They put this out in January of 2013. They knew that after a cold soak (apparently that is engineer-speak for turned off car and let sit idle for a time) that the engine might "run rough" at first, "rattle", maybe have a diagnostic code that indicated a cylinder misfire. Guess what - by that time it is too late! You already have coolant leaking into the cylinder at that point and you already have a cracked head gasket.
Maybe a seasoned mechanic can tell me I'm wrong here, but the way I see it, the intake manifold is the contributor to the head gasket failure. The EGR system in this engine sends exhaust to individual runners (or EGR port, whatever you want to call it) in the intake manifold, then onto each cylinder as part of the exhaust gas recirculation process. With the temperature control at the EGR valve and nothing to monitor the temperature at each individual runner, any carbon deposit build up that clogs an individual runner and increases the running temperature at that individual cylinder will cause that cylinder to run hotter than the other cylinders that have less clogging. This uneven temperature between the cylinders causes a differential expansion on the cylinder head and eventually causes the head gasket failure at that cylinder.
So, yes. The offer is out there to mechanics on this board. Tell me where I am wrong in this assessment of intake manifold - individual runners - carbon clogging EGR circuit - differential expansion on cylinder head - head gasket failure. I'll admit that I am no mechanic, so clarify any points I make that are wrong (as well as confirm any parts that are right).
Back to the real issue - what did Toyota/Lexus do about this, aside from putting out a few TSBs (also see L-SB-0019-16)? Nothing, that I can see. Lexus/Toyota has not been proactive with its customers to offer a solution to this problem that avoids major expense to the customer. There are a number of ways Toyota/Lexus could have saved it’s customers from undue expense. First, Lexus/Toyota should have made updates to the service schedule on this vehicle to inspect the car for clogging in the intake manifold. To my knowledge, they have never updated their service schedule to include this. Toyota/Lexus could have also offered a cleaning of the intake manifold at regular service intervals to avoid the clogging and cylinder failure that leads to the head gasket failure. Additionally, Toyota/Lexus could have required a complete replacement of the intake manifold by a certain mileage so the customer could avoid a head gasket failure. Any one of these proactive decisions could help your customers avoid the issues that lead to higher repair expenses on the car.
No, Toyota/Lexus knows. Toyota/Lexus knows there is a problem with clogging in the intake manifold and that this clogging problem contributed directly to the head gasket failure. But they chose to do the least they could do, and the owners of these cars are now getting stuck with the results of this negligence.
Question is, are we all just going to plunk down our hard earned money to fix a problem that could have been avoided if Toyota/Lexus did the right thing?