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2010 Lexus RX 350 Gas Tank.

sjerlsjerl Posts: 3
recently I just noticed my 2010 rx350 only had a 16 Gal gas tank instead of 19.2 Gal on the vehicle. Can someone please explained the different tank installed in vehicle?


  • ehiaehia Posts: 3
    I have been having problems with my tank volume ever since I got the car. My range has been 275 every time I fill it up. I have been telling the dealer and they said try premium gas which I believe was a bunch of bull, but I did and saw no improvement. How did you know your tank was smaller? What did the dealer say? Thanks
  • I'm curious about this too, because it would really seem to explain the lesser mileage range that I'm getting on my 2010 compared to my 07 also. I have been using regular unleaded, and at first, after I put the gas in, my cruising range will be at about 302 miles to empty. But it quickly drops by the next day, and that's mainly driving around town or back and forth to work which is only 5 or 6 miles each way for me. This has been the only disappointing thing on the 2010 for me right now.

    My stepfather also has a 2010, and he puts premium unleaded in his, and when I checked his gas mileage average read out on his vehicle, it was only saying 17 mpg.
  • I just purchased a new RX350 to replace my faithful RX300 (with 210,000 miles!) I was so impressed with the RX300, I wanted to get another RX. The new RX350 drives great but when I took it home to put my things in it, I was distressed with the new console and interior design.

    Where do you put your sunglasses? Where do you put your change and loose cash when you roll through a drive-thru? Where do you connect your IPOD? All I find in the console is a mess of cords to allow me to plug in my IPOD and phones, but there is really no room for anything else meaningful. I used to put, in the console compartment of the RX300, the important things I needed....wallet, checkbook, spare keys, IPOD, and even a measure of personal protection. I find NOWHERE to place these items in the console...and if they should fit, easy access it is not. The console sits so far back, I physically have to turn to open the console. And that thing (the hole) at the base of the console...what exactly can go there? A cube box of tissues is even too tall.

    I am not trying to be funny, but I test DROVE the car...who would have thought there would be no place for my things. I have found many lesser-end cars that have a better designed interior. Help! I am open for suggestions. This may sound strange, but I am so frustrated I would consider getting a different vehicle. Mistake to change or better to stick with it?

  • Do you have to use premium unleaded in the RX350 2010?
  • smarty666smarty666 Posts: 1,503
    First, never use the trip computer or mpg readouts on the vehicle. I have found time after time they are usually not accurate. Still the best and true method is to manually calculate the amount of miles on the trip odometer by the gallons of gas on the pump to the furthest decimal place if possible. Do that for several gas fill-ups and take the avg from at least 5 or more fill-ups and that is about as accurate as you can get.

    A lot of things go into fuel economy and gas mileage and a lot of factors out of our control, such as temperature, traffic, pump cut offs, etc. Also there are other factors that are under our control, how you drive (lead foot for instance), city vs highway, tire brand/class used on vehicle, tire inflation pressure, suspension issues, drag issues, brand of gasoline used, if the vehicle is loaded down, etc.

    Just for everyone's questions, the Lexus website says the RX350 comes with a 19.2 gallon gas tank and when I was shopping last year that's what the sales people told me so that is the size your tank should be. If it is not, then there is a big boo boo on your RX! Also, the fuel recommendation is premium gas so that is what should be put in it (91 octane or higher). I've come to find over the years, that when it comes to gasoline whether is says requires or recommends premium I put premium in. Not only did it keep knocking/pinging and engine idle issues at bay but it gives you maximum performance. I would not be putting regular in a RX if I were you. If you wanted to do that then you should have gotten a Toyota.

    Sometimes you can get away with mid-grade (plus) instead of premium but around where I live, the difference in price between mid-grade and premium is 10 cents so I don't mind spending the extra $1.50 a week putting in premium.
  • With my '07 RX, my service advisor said it was fine to put regular unleaded in the RX. I drove that car for four years just putting regular unleaded with no problems, and I felt that the car got pretty good gas mileage for an SUV. Now I'm driving the 2010 RX, and I'm still putting regular unleaded in it, but I don't believe I'm getting the gas mileage that I was getting in the '07.
  • smarty666smarty666 Posts: 1,503
    I would say that service advisor is an idiot. It wouldn't be the first time a persona at a stealership has given wrong information. I've had it happen on more than one occasion.

    Just remember, you only had the RX 4 years under warranty, God knows the long term affect of using regular (6+ years) and once your out of warranty. If something was to ever happen to your exhaust system or anything else related to it out of warranty, it doesn't mean jack squat what that service advisor said to you and you'll be blamed for putting regular in

    If the owner's manual says premium recommended or required there is a reason for it. You might be able to get away with mid-grade but not with regular. The car is designed for premium.

    This is just my opinion but I can't understand why you'd spend the money on a expensive luxury vehicle like the RX and then not fill it up with the recommended premium gas. Your not really saving that much money a year by putting the regular in vs the premium just to save a few bucks on a expensive vehicle for everything else (oil, tires, etc).
  • I guess we'll see what happens with the '07, as my sister-in-law is driving it now.
    Seriously though, it's not just the service advisor that has suggested this. I've also talked with other auto mechanics regarding using regular unleaded gas vs. premium on vehicles that the manual says otherwise. They've said the same thing.
    So, no, I'm not convinced yet about this.
  • smarty666smarty666 Posts: 1,503
    Well, I can't obviously speak for all vehicles, but I know my 10 Maxima say Premium recommended. I've been putting premium in and its been running great. I live in NJ where we can't pump our own gas. A few months back, the idiot attendant put regular in instead of premium. Before even leaving the station I could tell the difference. The car was idling terribly (steering wheel even vibrating heavily) and the car was struggling to go during acceleration, etc. It was jerking a lot when driving and the mpg went in the toliet. I had to take an easy with the car that entire tank until I could get premium back in.

    Some guys on a Nissan forum I belong have gotten away with mid-grade with no problems or reduction in mpg but no one is putting in regular. So some vehicles the grade of gas makes a big difference.
  • wwestwwest Posts: 10,706
    edited September 2010
    "recommended VS required"

    IMMHO required means REQUIRED.

    Recommended means you have the OPTION.

    For about the past 10 years now "high" compression engines have had the ability to run on regular fuel with no detriment, short or long term. First and foremost the compression ratio is pretty much meaningless except when the cylinder is getting a full A/F mixture charge.

    So the only times the fuel grade is important is with/at WOT, or close to WOT. The second is engine lugging, operating the engine in a to low gear range for conditions.

    With the advent of non-resonant, wide band, knock/ping sensors the engine control ECU simply uses the EFI PWM, duty-cycle, to slightly enrich the air/fuel mixture thereby alleviating any tendancy to knock/ping. In the case of lugging the ECU commands a transmission downshift.

    Slightly lower maximum HP/torque and FE, that's all.
  • smarty666smarty666 Posts: 1,503
    edited September 2010
    very true but its still a recommendation; they are recommending you put in a certain grade of gas; if you don't follow the recommended octane rating then do not complain about lousy mpg

    I can tell you from the experience with my 3.5L VQ engine that a high grade displacement engine, such as that one, would have a severe detriment to it if used lower then mid-grade gas so for some engines it still makes a difference. I wouldn't have thought it till I saw and felt how bad the car was struggling to go down the road with regular in it.
  • randy114randy114 Posts: 2
    My RX350 has a noise that sounds like a small motor running coming from underneath the car at times. The car may have been sitting for hours and when I walk by the car I can hear it running. I can't locate the source but it sounds like it is coming from around the rear of the car by the muffler or the fuel tank. Any ides?
  • kwbuggykwbuggy Posts: 11
    It is just a small fan which purges the vapors from the fuel system. It runs whenever needed. Can be spooky to walk out to your garage after the car has sat for hours and hear it running though.
  • randy114randy114 Posts: 2
    Thanks! I was worried that it might run the battery down.
  • I have a 2010RX 350 and never noticed any difference putting regular or premium fuel and did numerous MPG test - no difference. Performance no difference. And to the point of voiding a warranty how would anyone be able to determine. My service advisor told me she has a 350 and uses regular gas and she talks with certified service techs everyday. Here some math. I drive 25000 miles a year
    25000/22 mpg= 1136 gallons per year x 5 years = 5681 gallons
    5681 gallons times .35 gallon= $1988 savings. That's worth thinking about especially since there is no improvement on gas mileage or decrease performance. Consumer reports advises the difference between high octane gas "recommend vs required" such as a turbo engine. Just saying if there is no clear advantage why spend the money?
  • jodar96jodar96 Posts: 400
    Gas tank capacity has always been an issue with RX. Our 2014 RX330 AWD never took more than 17.2 gallons. No matter how dry the tank was. Our 2010 is the same. Both tank say capacity is 19.2 gallons. There is such a thing as " non usable volume." in fuel tank system. The gas in channels and grooves that is not accessible to fuel pump inside the tank.

    As far as premium gas for 2010 RX350, with some of the comments above, I will start using regular unleaded. I find it annoying that 2010 is to use premium and later years use regular unleaded. In the old days, premium gas was $0.15 more. These days they charge up to $0.50 more.

    I have a 2009 Mercedes E350 that requires premium and I will always use premium in that car. With Mercedes, BMW, Audi, they all require premium. They don't go back and forth between the years.

    It is strange that the sane engine under Toyota brand uses regular and under Lexus, it should use premium.
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