OutlawTita

iTrader: (1)

Since everyone has different driving conditions and different driving habits as well as different maintenance routines I believe the right answer is that "it depends". The Lexus V8 engines are almost bulletproof and if you drive far enough to get the oil to operating temperature, use a decent oil filter, and do 3K mile Oil Change Intervals (OCI) --- then it probably would run 300,000 miles on WalMart's Super Tech dino oil. If you "really want to know" what oil is best for your specific application then I believe you need to run a few analysis of your oil to help you determine what your optimum OCI interval is for the type of oil you use and your driving style/conditions. It is not that expensive and you can learn a lot.

m.skeen

Do the dealerships use synthetic?

I bought my SC back in Oct (dealership just changed the oil) and then I changed the oil back in January (~4000 miles) but I used Castrol GTX 5W30 with a Mobile 1 filter. I don't mind paying for synthetic so should I go back?

sc400

Stay with regular oil and save your money. I doubt that those who use synthetic could offer any scientific evidence on its performance/cost ratio.

I tried out synthetic but it did not offer any better mileage so I switched back. AND I could backup my case with actual mileage.

For the last 4-5 years I have been getting approximately 320 miles between fill-ups. Whenever I get close to 4K or the gas mileage would drop to 280 per tank I know instantly it's time to change oil. Well... I tried out Mobil 1 syn and eventhough they claim it's 7500K guaranteed by the time it's 4K miles my gas mileage drops to 280 per tank. Now I can either continue on to 8K with 280 per tank or just change the oil to get my normal 320 per tank.

It's fairly costly to use synthetic oil and get the same gas mileage as my regular 5w-30 so since then I learned to change oil at every 4K. Synthetic or not it didn't make any difference but it did save me money using regular oil.