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I've read on forms ppl that lease and know they're not keeping the car won't take time to change the oil and put whatever fuel that will run in it.
It's always a gamble unless you look up the maintenance records, just like you would when checking for accidents. I believe ppl on this form actually care about their vehicles.
Maintenance records aren’t going to show what gas was used. I think the fact that there are 90 posts shows people are looking for excuses.
Maintenance records aren’t going to show what gas was used. I think the fact that there are 90 posts shows people are looking for excuses.
True point, just anything that makes it run. Disappointing ppl having nice things and don't take care of it. I've leased (2) RX350's and all service was done at the dealer. When returning it's showroom condition. The last one stayed on the lot for 3 days it had 23k miles on it..
Filled up today for $5.29 Premium. Regular was $4.99.
My take on it is you can afford to drop $60K+ on a Lexus,
the 30 cents more for proper fuel isn't that much.
The manual for the base Turbo engine is not ambiguous: Gen 5 RX350 User Manual - Use 91 Octane
For comparison, here is the fuel recommendation for the RX 350H. In this case, based on engine and tuning, Lexus recommends 91, but clearly indicates it's also okay to drop down to 87. Gen 5 RX350H User Manual - 91 Recommended, but 87 Octane Acceptable
(And the 500H has, in essence, "use 91 or higher" - not doing the recommended/minimum terminology used for the 350H)
In an emergency (one off if you can't find premium, or for a single tank coming off the lot), you should be okay dropping to a tank of regular in the non-Hybrid RX 350, but Lexus is clear that for standard use, your regular gasoline fills, use 91 (or higher).
I've been driving RX for 25 years, since the original RX 300. I talked to my dealer's service people (who I've known a long time) - they were very clear that you should really use 91 or higher on the base 350 engine, as required by the manual.
"Hoping" things will be okay by using regular gas most of the time is begging for problems. Modern engines do have a range of adjustments, but it's a finite zone.
Filled up today for $5.29 Premium. Regular was $4.99.
My take on it is you can afford to drop $60K+ on a Lexus,
the 30 cents more for proper fuel isn't that much.
Difference in NJ is much greater. 3.19 vs 3.89 or so.
The gas stations near us tend to go 87 - 89 - 93 (no 91), and the 93 is consistently 25% more than 87 octane. When I filled today regular was 3.40, 93 was 4.23.
Hello Friends,
OK, so I did some research on this subject as to why our RX350s require premium gas when the apparently identical engine in the Highlander does not. Here is what I found, and any mechanics please feel free to weigh in or correct. The Lexus engine requires premium gas because it has higher compression than the Highlander, and with lower octane gas it may knock (improper ignition of the fuel/air mixture, not good!). The Lexus engine has a knock detector which tells the ECU to adjust the engine timing if it detects knocking - the detection method is engine vibration (again, not good). Notice that the ECU does not know the octane or care, only that once the engine starts knocking, it adjusts the timing to stop it. It does not adjust proactively.
I do not plan to experiment with how effective the knock sensor is in limiting engine damage.
YMMV.
Jim H
I tried to get away with regular in my wife's 2000 ES300...our first Lexus....wound up having to replace both knock sensors. One at a time of course for twice the fun! Went back to premium and no more issues. Mid grade at altitude. Always used premium in 2008 RX350, with never an issue. Was surprised and delighted to find 2012 with more or less same engine, but with a touch less compression/power is happy with regular! I've seen price difference in different parts of the states anything from a few cents to over a dollar, all depending on how much they think they can get away with in their particular situation. If you can afford to drive anything, let alone a Lexus, you should use what you need to keep it happy! And it might be cheaper in the long run too.
Keep in mind that mid-grade is not acceptable at high elevation in a turbo engine that requires premium, the way you can run mid-grade in a naturally aspirated engine that requires premium.
Keep in mind that mid-grade is not acceptable at high elevation in a turbo engine that requires premium, the way you can run mid-grade in a naturally aspirated engine that requires premium.
Then again high altitude mid-grade gasoline sold in some areas is only 87 octane which is the octane of regular in most of the country.
I've been using regular octane gas (87) on RX350 for a couple months now. So far didn't feel any difference from 93 octane gas. No engine knock, no loss of power, no matter if it's 30-degree or 90-degree day, car runs the same, even did multiple wide-open-throttle pulls, no knocking.
This is to test on the claim in this link that our engine is the same as the ones in the new Highlander, and they can use 87.
So, go ahead and try it if you don't want to be ripped off by premium gas (of course do it at your own risk and I'm not responsible for any loss or damage to your vehicle )
02-25-24, 02:50 PM
(of course do it at your own risk and I'm not responsible for any loss or damage to your vehicle 
)