rxets

Just have a friend to check this insides my dealer.

They don't usually carry this 0w-20 until this RX10 arrives. Although '09LS and '09LX are also ok with this viscosity oil, they can also use 5w-20, the common one, in most of weather conditions.



They inked 5w-20 on my receipt for the billing purpose, but they did pour 0w-20 into my car.........

Jerry61

The first number is for winter 0W or 5W. In cold weather you want your oil to be thin when you first start it up to get to the top of the engine. After it warms up to operating temperature it should be 20 weight oil. Here in the deep south I have customers who want to run a thicker oil because of the heat. I inform them if they are using a good synethic oil which is designed for heat and stress and the vehicle calls for a 20 weight oil that is what you should use.

ThChinaman

Well, since this is back, I'm going to poke the oil viscosity bear.

I've somewhat recently ended my prepaid maintenance contract so now I've been doing my own fluid changes. Never really paid attention to what the dealer has been pouring into the engine but I do know that the MPG reading shows ~14-16 when they were doing the changes. When I did my own drain and fill with M1 0W-20, I've been noticing that the MPG shows ~12-13 now. I don't think my driving habits changed. Could the dealer have been using some other oil that would lead to better mileage? San Francisco, not too cold, not too hot.

Clutchless

I do not think there is oil much thinner than 0w20. It could be related to brand differences in viscosity. According to the folks at bobistheoilguy.com the Toyota 0w20 which is made by ExxonMobil, is more viscous than Mobil 1 0w20 oil. It also has a more robust additive package. Those are some of the reasons they claim it is a better oil.
What did you put into your engine? Do you know if your dealer was using Toyota oil? Some do not.

lexus114

this is why i change my own oil, by the way, the service manager at my dealer told me it is perfectly fine to use 5W20 synthetic motor oil. besides. it is still a 20 weight oil anyway.

ThChinaman

Not sure what the dealer was using. I'll send them an email. I emailed Mobil1 a while back about whether or not they still made Toyota oil and they said yes so I assumed Mobil1 would be about the same. I put in Mobil1 Advanced Fuel Economy 0W-20.

Clutchless

Mileage does typically get worse in the winter months. It also affects (lowers) your tire air pressure which many folks forget to top up. This lower tire air pressure also makes mileage worse. However, I see your sig indicates you live in the SF area where it is pretty moderate all year.....

fastnoypi

Good point. Winter fuel blends also adds to that lower mpg

carguy75

0w-20 is the oil to use and I use Mobil 1 Fuel Economy oil.

http://www.mobil.com/USA-English/Lub...il1_0W-20.aspx

I do not know if it is really a better oil than the Toyota Brand 0w-20 oil, however I change my oil every 5k miles which is half the time Lexus recommend changing the oil so Mobil 1 should not be an issue.

I usually average about 20-21 mpg when using the Mobil 1 oil, sometimes as low as 18-19mpg in really bad stop-and-go traffic.

I have the AWD model so I guess that the FWD models would get better mpg while using the Mobil 1 fuel economy oil.

FYI, I have a heavy foot.

My wife gets even better mpg(about 2mpg more) when she drives the cars.

ThChinaman

I don't think my tire air pressure is low but I'll check it out. Maybe it is somehow the whole winter thing. An potential air leak somewhere in the intake wouldn't affect it much would it? Maybe if it was after the air flow sensor? Not too knowledgeable about that stuff. Ran an oil analysis at 60k and they said there might be dirt contamination and should check air filter/intake.

Carguy, 20-21 sounds high to me for a 350. I'm assuming that's mostly freeway driving for you? I can get ~22 if I do all freeway after a fill but it drops pretty quickly once back on streets.

Sorry. Kind of getting off topic.

carguy75

No actually it is a 50:50 mix of highway and city driving.

I do use 93 octane Shell V-power gas only and use a high performance air filter(UpGR8 brand) as well.

http://www.upgr8.com/store/oem-repla...ir-filter.html


The 20-21 mpg(actually settles on 20.4mpg mostly) is when I can drive the posted speed limit with less congestion and have the ECO light illuminated.

Like I posted earlier ,my mileage goes down to 18mpg in heavy stop-go traffic.

To be noted also the mileage goes down to 16mpg if I step on the gas to pass or just have fun, but usually goes back up if i drive responsible enough for the ECO light to turn back on.

FYI, I do have my cold tire pressures set to 36psi front and 38psi rear which may also account for the better mpg in conjunction with the new air filter and 93 octane gas.

The Lexus handles like a dream to me with the higher tire pressure, before with 32psi in all tires cold the RX350 felt like it was very sluggish when turning,accelerating,etc.

ThChinaman

Wow, that's pretty good mileage for half half. I use the same gas either from Shell or Chevron. I do drive a bit over limit though but not much. I'll bump up my PSI some more and see how it goes. Thanks

hovbuild

Wow! I have an 2012 and use regular. Drive mostly secondary roads and highways. In the summer with 36 cold PSI I get an average of 23-24 if I don't play around, in the winter 21. Southern Nh got some great cruising back roads.

carguy75

LOL.

I just drove the RX to work tonight and drove the speed limit all the way(which is very hard for me to do) and I averaged 23mpg(actually 22.9mpg) when I got to the job.

Traffic was pretty light tonight so I only had to slow down at the stoplights.

Very good for a SUV, however my 2014 KIA Optima with the turbo gets 30mpg when I drive slow and easy and average 22mpg when I get on it.