Yes. 1,000 miles after the new pistons were replaced i took the car back. I had a code and when they checked inside the motor, the carbon build up was showing up again. - somehow. They took the car back for 2 weeks, sent results to Lexus corporate, and was told my claim was denied. My SA believe that means something bigger is about to happen with the issue. I really hope so, because if further repairs were rejected and there's no solution from Lexus corporate, i will not be keeping this car past my CPO warranty expiration.

It doesn't lead to failed pistons. A lot of people seem to think this. It's just that if you experience carbon build up, there are new revised pistons Lexus is installing under the revised TSIB that is meant to reduce carbon build up.

If you have bad carbon build up, you can always have a top engine clean done (few hundred dollars) if you're outside of the warranty. But as others have said, due to the design of the engine, carbon build up will always be more of a "when" then an "if" issue.

 

What would happen if you do your own oil changes instead of going to the dealer? Would they not perform the TSIB since they dont have a record of the maintenance?

 

LIke others have said, changing the oil has little to nothing to do with the carbon buildup caused by poor design of the direct injection system in the IS250. Regardless of that, I think if you showed receipts of purchasing oil on a regular basis and changed it yourself, they cant hold that against you.


I think people's best bet would be to have a top engine clean performed every other oil change or 10k miles. This should greatly reduce the chance of carbon buildup getting so bad thta it causes performance issues. Some people swear by seafoam by having it injected into the intake manifold through a vacuum line, but if you're uncertain of the method just bring it to a reputable shop and have them do it for you. It should be a good and inexpenseive way to maintain the IS250 valves and rings.

 

I already went down that road with the same issue. I was fortunate to be able to work it out with the dealer. Long story short, the dealer did the repair on their goodwill.

Here is my story.
https://www.clublexus.com/forums/is-...ne-repair.html

My story/experience may help you to win the battle. Just be nice and respectful. Do your research before negotiating so that they don't trick you into doing something unnecessary.