Question for all you Lexus owners

[BigD1]

My 2006 Lexus IS350 with the 2GR-FSE dual injection at 145,000 miles has no carbon problems. Owners manual says to change every 5,000 miles with 5w30, and that's what I do.

The IS250 engines with direct injection had the carbon problems, but Lexus was rebuilding the engines if they could get them to misfire.

It's your car, and you can do 10,000 if you want. On the other hand, there is no way I would do 10,000 mile oil change intervals. Those engines are just too dang expensive, and oil is cheap. From what I have read, these engines can't be bored over.

 

[Ethan1]

Originally Posted By: andyd
My commute was able to keep my 528e carbon free. MDW's around town driving in her 528e carbon-ed up. A coupla 25 mile runs down to the Canal in 2 would cure it. About the 70 K Acura with coked rings. What happened to the original engine? Granted it would be several hrs labor, but labor and a gasket kit would have fixed the engine


Generally the manufacturer requires some calculations about whether repair or replace is more cost-effective. They might do the calculations themselves before they approve anything. Then the engine core is returned to the parts department and the manufacturer may call it back for analysis/verification.

 

[HangFire]

Originally Posted By: PimTac
I think 5k oil changes with a major brand of synthetic that meets Lexus specs will serve you well.


I don't agree. Oil volatiles (as measured by Noack) is a major cause of carbon valve buildup problems on DI engines. Changing too often means more volatiles. If you run synthetic 0w-20 in a DI engine, IMHO stick to the 7.5K to 10K OCI range, as CELICA_XX said.

 

[CR94]

Originally Posted By: HangFire
... Oil volatiles (as measured by Noack) is a major cause of carbon valve buildup problems on DI engines. Changing too often means more volatiles. If you run synthetic 0w-20 in a DI engine, IMHO stick to the 7.5K to 10K OCI range, as CELICA_XX said.
Yes, volatility may be a significant factor, but the issue was carbon RING groove buildup, a common problem on some engine models, including non-DI ones. How best to avoid this on susceptible engines isn't clear, despite much speculation in various posts above. I believe posters in other threads have have reported Honda blames it on the combination of going WOT before the engine warms up, and questionable gasoline quality.