funny 5w30 nothing else, the high quality synthetic is the important piece with cold starts
why complicate

 

Just got an email from the service manager at the Lexus dealership and he states that he talked to the mechanic and he did use 5W30 in my LS430. He apologized for the mistake on the invoice which showed synthetic 0W20... He blamed it on the labor operation that was entered into the computer. Sounds a little fishy to me. LOL. Also said he would credit me $18.53 for the mistake. Why did he also tell me that they use 0W20 in the LS's... I think I'll drain it out in Spring, if we every warm up, and pour in the 5W30 Ultra I have. Last time I get an oil change at the Lexus service department.

 

Glad you got that clarified. I was going to call my dealer and check what they are using...

 

Lexus chart showing oil compatibility for all models and years here -

https://www.clublexus.com/forums/rx-...back-spec.html

 

Pennzoil did not engineer and test the UZ engine. I would be highly skeptical of trying to improve on the specified oil weights. Those oil weights were determined on testing in a range of weather conditions. Heavier weight oil viscosity, even in warmer climes, may be too thick on start up. 237K miles on 5w-30 dino oil and no problems on my '01 that has lived only in the upper midwest (Illinois and Michigan). Synthetic oil as a substitute is fine, but not heavier weight oil, IMO.