Flash5

Technically it shouldn't because it is a Toyota part and also they wouldn't even be able to tell unless they took it off the car and looked at the part number. They look exactly alike, I honestly couldn't tell the difference visually, just the rubber in the RCF/GSF ones are slightly stiffer.

AVIAT0R

Here are the part numbers for RCF LCA Bushings:

48075-24010
48076-24010

E46CT

Here's an IS200t intake valve at 60,000 miles. Practice good cleaning/driving habits while you can. Use techron regularly and use good oil w/ SN plus designation (formulated specifically w/ chemicals that mitigate carbon build up w/ a special molecular chain) I imagine most oils today you'd use would have this but be sure. I know Amazon 0W-20 does =)

Carbon deposits on the valves might prohibit seating which would cause low compression and/or misfiring and the carbon on the valve itself would generally cause poorer flow. This is the result of these engines using at least partly, direct injection.

TonyN

iTrader: (1)

Mine last about 12k all stock
I did the RCF lower control arm bushing and rear SPC camber kit, I also went with all season tires, I'm at 10k with this set up and no signs of wear and expect 3k or more out of these tires.
I do about 20-24k miles a year.

The dealership should not even know you switched it out because it's a OEM part, unless they pull the part number to verify but even then its OEM.

Tharr62

Oh man.. I assume this is not good! Is this common, or is this because the owner slacked off on oil changes / did not care? Does that happen to the 350 engine as well?

TonyN

iTrader: (1)

It's due to the design of direct injection engine, the 350 does not have this issue because it only uses port design.
The is250 had major carbon buildup issues and the new 200t engine uses a combination of both.
The 4cyl turbo uses both direct and port injection, it also cycles between otto, Atkinson, or the combination of both depending on engine load and rpm. The driving habits plays a big part for the new 4cyl turbo because of the engine load and speed determines which injector cycle is used, if your on the highway in low rpm and high load cycle then the port injection are not being used to clean the valve, on medium to high acceleration then the combination of injectors are used so you will get some cleaning of the valves.
The new design is really ingenious and there is so much more to it then the basic above, it comes down to find the happy place of mpg, power, and knock prevention. Little known fact is the region of air, fuel, and timing that has the best mpg is also where the most kocking occurs.

In short, give the old girl a little bit of gas once in a while.

Tharr62

This is something I was wondering the other day! (the above info was amazing BTW). So, basically when I cruise around town all soft and careful it's building up carbon (not good) and when I am driving more sporty.. its actually good for the engine.

So, in real life application if I drive say 5 days a week around down and go say a tank of gas all soft and efficient, and then on Saturday I paddle shift my way on the high way for some quick fun, would this be enough to burn off the carbon?

The gas near me is Mobile. I saw use Techron (Cheveron)? Is this really going to make a difference?

Lastly, if I get lots of build up like that.. is that fixable? or is that where the motor is just gone.?

Tharr62

I am surprised to see this on this engine. I just learned about DI and how it works (YouTube) and one of Scotty's videos. He actually mentioned that in modern engines with both systems (like the 200t) this should not be an issue (Carbon build up), yet your photo shows it? Lexus seems to be using (offering) the 200t in a lot of their cars and SUV's now.. What do you think, is this engine still a magnet for build up.. or was this an isolated case?

E46CT

Apparently the port injection will activate under certain low load scenarios and other conditions as well. but not all the time obviously. So the fact that the car runs on direct injection part time means there will still be some carbon build up. Frequent oil changes using SN plus designated oil will help. Also mix up your driving. driving too easy all the time or too hard all the time isn't ideal. Let the engine get hot and run low load frequently to help mitigate carbon. Techron and seafoam occasionally probably wouldn't hurt either.

Tharr62

I got my car used from the dealer. 2016 200t with 23K on it. I of course have no idea how the previous owner drove it.. are there any signs that are easy to spot to see if there is already carbon build up going on? Looks like I really should have got the 350 :-(.

I'm trying to find reasons to love this new (to me) car and motor. But, I have to keep this one for at least 7 years (long story) and need it to last. Honestly, I saw the car fell in love and trusted "Lexus" from my RX350 and my wifes ES350, and now her new RX. I did not bother to do a bunch of research on the engine type, or tires, or anything like that.. LOL. and now in just a few days I have learned a lot!

- Tires are not going to last very long (need to do that LCA bushing upgrade)
- Known issues with the Valve module going bad for the turbo
- Now worried about carbon build up.

Part of me is annoyed.. why cant they just make the injection system to CLEAN the engine in ALL the engines. LOL.

I guess the IS is MUCH more of a "sports car" than I thought it was. The ES would have prob. been the better buy for someone like me who wants ZERO issues. But, the problem there is that car is very bland.. and I fear would get too board with it, and then might get an itch to make a change sooner then I can this time.

Flash5

Don’t worry so much about carbon buildup. Almost all cars have some build up, you can’t have shiny new parts forever lol. Just DI engines would be much worse, but they still work fine for the most part. Just drive the car and enjoy it while doing the required maintenance and you should have no issues.

E46CT

The cost of the LCA bushings and the labor involved (I assume you won't be doing it yourself) AND the alignment would likely match or exceed the cost of a new front set of tires. So consider your driving style.

I'd only do the LCA upgrade if you are driving very aggressively (I doubt it) AND using high grip summer tires (also doubt it). It is less of an issue for those who drive reasonable and drive on longer lasting tires.

You are just hearing some enthusiasts recommending this. It does not reflect most scenarios.

Also keep in mind the LCA bushing "upgrade" would likely not eliminate the wear, but just mitigate it somewhat. You are STILL not out of the woods.

This is still a pay to play car.

You are correct the ES350/h is a better "set it and forget it" type car. The new ES has handling chops to back it up, it wouldn't bore you.

And they do make injection systems to clean the engine all the time. It's called older cars, or simpler cars like the Corolla, Camry, Prius. Those cars are reliability fortresses, so they use old style injection. The newer more faster cars need to compete in competitive german markets. Lexus can no longer play the conservative game since they need to keep up with MBZ and BMW.

You'll be fine w/ your IS. Just maintain it and enjoy it.

EZZ

I think you are over thinking it. The LCA bushing upgrade takes less than an hour with a decent mechanic once you get the part in and the carbon build up isn't that much of a concern. I've yet to see anyone on the forums really complain about it. Just drive the car and if things pop up, a dealer visit isn't the worst thing in the world. My IS350 has near 60k miles and i drive like i stole it. I literally average 16mpg due to my lead foot. But, its held up very well. Not a single creak in the cabin yet

EZZ

The total cost of the LCA bushing w/o alignment is $160 ($80 parts, $80 labor). The alignment would be $70 additional which i didn't get (car drives straight as an arrow still). The cost of one of my PS4s is $300 so the LCA bushings are a cheap upgrade.

E46CT

Front set of Firestone Indy500s are $180. with the LCA wear problem, you're often replacing two sets of fronts during the time you'd wear out one set of rears.