maxx430

I been reading alot about the Lexus CT and seen people saying the head gasket issue was address for the 2015+. have not seen any real evidence. Anyone know if something in fact was changed?

spiral

Yes. They changed the pistons first, then the following year changed the rings. But on top of that they reconfigured the EGR system. The years are escaping me at the moment, but I’m thinking it was ‘14 Piston ‘15 rings

found Mendel’s chart on prius chat

[img]blob:https://www.clublexus.com/b00a9228-041c-478a-940c-3590b05705db[/img]

spiral

E46CT

Also intake manifold was revised for 14+. but still, it's recommended to change oil at 5k instead of 10k as well as do somewhat regular egr pipe/cooler/valve cleanings to help mitigate the problem. It's also believed Toyota made a 3rd revision to the headgasket material and build with the most recent being done on 2014+ cars. The part # is the same though but some have noted visible changes.

internalau

What are telltale signs of EGR-related issues besides rough start and idling and decreased MPG?

E46CT

Maybe others can chime in with experience with this problem but as far as I know, those are the tell tale signs. You don't know until it's too late. That's why it's important to just make sure the EGR circuit and engine oil are kept clean. All in all though, i don't think the problem is as widespread as internet forums would make you think. Plenty of 3rd Gen priuses with 300-600k miles doing hardcore taxi duty on the original powertrain. 2010s too.

also important is keeping the engine coolant clean. bad coolant will eat away at your headgasket further exacerbating the problem. the types of people to own priuses don't really maintain their coolant or anything else for that matter which i think can be a detriment to it. its reputation of being a low maintenance car hurts itself in a way

KKM

Don't wait for telltale signs, for the older model with the original design, it should be on a regular preventative maintenance schedule. For my '12, I did it at 70k, wish i did it at 50k or sooner. Will do it again at 110k when I flush the coolant and change the spark plugs.

If you want to get an idea to see how gunky it is, pull the EGR pipe, which is easy, follow Nutz About Boltz's video:
After I saw my EGR pipes condition, it prompt me to clean the EGR cooler and intake manifold (replace the PCV since its right there)..