FYI on Synthetic Oil

cranheim · 2007-07-10T19:20:56+00:00

Ever since I bought my 2004 Sienna, I have been considering using Mobil 1 synthetic oil. The main reason I did not do so, was because of Toyota's written statement saying "It is OK to use Synthetic oil, but if you do, you should not switch back to conventional oil". They refused to tell me why. I just noticed a few days ago, this statement disappeared from their Customer Care website. I wrote to them again asking if their position on this had changed. This was their latest answer:"Toyota has not found there to be an issue with switching back from synthetic oil to conventional oil so long as you are consistent with the maintenance intervals as described in the Scheduled Maintenance Guide. Your email has been documented at our National Headquarters under file #200707090676. If we can be of further assistance, please feel free to contact us".I stayed away from Synthetics because I was not sure if there was some technical reason why going back to conventional oil, if I chose to do so, might cause a problem in the engine. This statement seems to clear the air on that one. Charles Ranheim