I'm headed to get my 10K "oil change" on Saturday. I purchased Mobil 1 5w20. I see the dealer used 5w30 at my 5K, but can anyone give details on the 5w20 tsb. I've heard a couple things, but I don't know which visc. grade to use. I figure I'll stick with Mobil 1, but would like to know more details. Can anyone help me out :-)

BTW, I bought my car new in May and already have 10K (62 mile round trip for work). So far virtually no issues, not a penny paid to date in maintenance until now. Paid $20 for a Bosch cabin filter and about $20 with shipping for the OEM air filter from Sewell and installed myself. Coming from a Mercedes previously I'm loving the lower cost of ownership and added reliability! I figure I'll pay the dealer to do the oil and filter change and inspect my brakes for the 10K. I may be able to stay under $110-$120 in maintenance for the first 10K despite using more pricey Mobil 1. Love it! Love it!

 

I use Mobil 1 5- 30 in mine regardless what TSB Lexus comes out with.

Basiclly the 5- is for cold temp. & the 20-30 is for hot temp. Your owners manual gives you the exact range for each viscosity #

 

5w20 is fine....you will noice the mpg increase after a while.....

 

https://www.clublexus.com/forums/sho...01&postcount=9

 

I, for one, have notice a mileage increase after putting in RP 5w-20

 

I've been wondering/obsessing about the appropriate oil for my 350 also. I bought a case of Royal Purple 5/30 to put in my wife's G35 as it only calls for a SL rated oil. Since the IS owners manual is so vague as to the oils you can use "Use Lexus approved oil", I called Lexus to ask if RP would be an approved oil.

They said it doesn't require any brand, just 5w30, and transferred me to my dealership. I didn't get to talk to a tech at the dealer just the service advisor middleman, but they put me on hold (presumably to ask the tech) and they came back and said RP was fine, "just make sure it's 5w30". Granted, this could just be dealer ignorance but both Lexus corp and the dealer indicated 5w30.

I'm still not sure which I want to use, but thought I would throw that out for general consumption

 

if you want to stick with 30 weight oil...you can also try 0w30 motor oil for cold conditions...

5w20 for me and it did improved the mpg

 

I just changed my buddies oil with Mobil 1 0W20 for energy conservation and he noticed the mpg after the first fill-up.

 

i'm using mobil 1 0w30, just switched from 5w30

 

how much more mpg increase are you getting from this change? I have been getting increase of .3mpg since i changed over to synthetic oil anyways. I am up to 26.5 mixed driving.