I've read several on here talk about this issue. I checked the service records on my car and this shows up.

Dealer Reported 01/12/2012 Park Place Lexus of Grapevine 20602 1016635 REPLACED PISTONS AND RING SET, TESTED OPERATION

Would this have been done due to the Carbon Build Up?

 

Yes


10char

 

Is this something that will continue to happen, or was it just on the Factory OEM parts?

 

I just had this piston replacement done on my 250. Apparently it happens to all 250s, some just sooner then later. From what i understand the carbon TSB replaced to pistons to the current ones used on 2010+ 250s. The new pistons are supposed to reduce or slow the carbon buildup. But if you drive the car long enough eventually the symptoms may return. However, at that point the solution would be a much easier top engine clean, which i think is only a couple hundred bucks. There are also some people who put oil catch cans on their car to further prevent the carbon buildup from happening in the future. read this :

https://www.clublexus.com/forums/is-...xperiment.html

 

do i need to be under warranty to get the fix?

 

Aspeckt, search the threads. Lexus sent out a letter about this. I believe it extends the warranty for this issue to 9 years and unlimited miles. So your 2007 is250 would be covered. but only if the dealer can replicate the issue. It took me several times before they could. if your experiencing any of the symptoms def bring it in to dealer.

 

they are still using OEM parts, but yes it is bound to happen again at some point or another. probably not in the amount of time you keep ownership of the car if you lucky. its just the design of the motor(more so the fuel system than anything else)