MPG-o-Matic Lexus RX400h Review Summary: The RX400h is a luxury five seat sport utility that competes with the Acura RDX, BMW X5, Cadillac SRX, and Mercedes R-Class (among others) . While that’s a crowded field, the RX400h’s hybrid drive train sets the luxurious Lexus apart from its most worthy competitors.
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The RX400h is one of the greenest SUVs on the market today.
The EPA gas mileage estimates for the all-wheel-drive 2008 Lexus RX400h are 26 city / 24 highway miles per gallon (MPG). In a week of driving, we found those estimates to be a touch low, as we achieved a combined average of 27.4 over 300 miles of driving in weather that ranged from forty through sixty degrees.ﾠ
Set aside whatever preconceptions you might have about hybrids.ﾠ
The RX400h is fitted with a 3.3 liter V6 engine and a Lexus Hybrid Drive system with front and rear electric motors. The drive train is rated at 268 horsepower, in total.ﾠ
It may be fuel-efficient, and a Super Ultra-Low Emission Vehicle at that, but there’s no denying that this 4,365 pound SUV gets up and goes.ﾠ
Stomp on the gas pedal and the RX400h will accelerate from zero to sixty in 7.3 seconds.ﾠ
Inside the cabin, you’ll find a cavalcade of creature comforts, with nearly everything you’re looking for, with the possible exception of an iPod jack.ﾠ
Our test RX400h was kitted out with genuine wood interior trim, leather seating, memory power tilt-telescopic steering wheel, heated front bucket seats with memory, cool blue illuminated entries, memory mirrors, and an array of cubbies.ﾠ
The navigation system provides a handy backup camera and an energy monitor to provide real-time feedback on the RX400h’s fuel efficiency. With just a bit of effort, family and friends will marvel over your gas saving prowess.ﾠ
Families will love the wide, roomy. and flexible interiorﾠ
A split fold down rear seat with center pass through accommodates skis and snowboards, while the automatic rear entry hatch eases loading chores.ﾠ
The RX400h is well-suited to the sport minded, as long as you don’t plan to drive off the beaten path or over the sand dunes to your favorite beach.
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Make no mistakes about it. This is not the SUV you want to take four wheeling. disclaimers in the marketing collateral clearly state that “The RX 400h is not designed to be driven off-road.”
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This family room on four wheels easily handles the everyday adventures of shopping, sports, and an active social schedule.
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RXs have found a home in many a garage. With the 400h hybrid, Lexus has extended the appeal of their popular five-seat SUV to upwardly mobile moms that think green.
– by Daniel Gray
I am very disappointed with its gas milage! I just bought a 2007 Lexus RX 400h with 52,000 miles and drove it for 40 miles (highway and local mixed). It gave me only 23 MPG!!! Maybe I bought a lemon? I will check with a Lexus dealer to see what they will tell me. Any suggestions?
Wayne –
To get the best mileage from the LX400h, you’ll need to adapt your driving style to take advantage of the hybrid synergy drive system.
I’d reckon that you’re driving with a heavy foot. 🙂
Turn on the fancy LCD display. Keep an eye on when the system is using pure electric power and optimize your driving style to maximize glide time…with your foot off the throttle whenever possible.
Dear mpg-o-editor:
I disagree with you. I found many other people complaining about their low mpg with their RX400h.
I guess Lexus hybrid system is still inmature as some vehicles do achieve high mpg as claimed. Advise to future buyers: always test its mpg sufficiently to see if the vehicle can achieve the claimed mpg before buying it!! My understanding is that there may be many lemons out there and Lexus will not be responsible for these low mpg lemons.
Wayne –
If you disagree with the FACT that getting the BEST mileage from a hybrid requires a CHANGE in driving style, with all due respect, we’ll just have to agree to disagree. 🙂
I spent a week test driving the RX400h in real world conditions, as I have with most of the other hybrids currently on the market. I had no problem hitting the official estimates.
It’s largely a question of driver training.
One other thing to keep in mind …
Generally speaking, hybrid systems require that the conventional engine be warmed up to facilitate the transition to electric power. This can significantly effect mileage when taking short trips in cooler climates.
mpg-o-editor:
You win! After I changed my driving to mimic a real old man’s real slow acceleration and stopping, the MPG increased dramatically to over 27 MPG! Thanks for your advise!
Wayne –
Heh. It’s what you do *after* you’ve accelerated to speed that makes the biggest difference. I love to stomp on the pedal when necessary. 🙂
Once you hit your target speed (or a tad above), take your foot off the pedal. When you reapply pressure to the throttle, use the lightest touch possible to maintain speed.
By keeping an eye on the current consumption MPG numbers on the LCD display, you will learn to modulate your right foot at all speeds.
At lower speeds, try to provoke the hybrid drive train into electric mode whenever possible. The goal is to glide when you can …
Great Review and observation! Maybe I drive too light-footed, but I actually pushed my Lexus RX400h 4WD to 29MPG average! I do most driving on highway and country roads. My only disappointment is its demand for premium fuel which to me, compromises the whole point of fuel economy. Sometimes I am tempted to go for mid-grade. What do you think?
I acutally heard you could put in the lower grade as considering that the premium fuel only helps with performance but as for gas the mid-grade actually is more fuel efficient… I have a RX400h and my husband drives a GS 350 and what he does is he put mid-grade in and after every three fill ups he puts in premium. But he found that he was gettings better gas mileage when doing that. So i guess what ever works for you. Just a suggestion..
we just got a 2007 400h and i can keep it at 8.9 l/100 km which is 26 mpg in the city. like the guy says, you need to drive the vehicle in the way that maxes out its use of electric drive. pretty easy to do seeing as they give you the graphical display of where the car is getting its power from.
essentially, any time you are either lightly downhill, downhill, or approaching a stop ahead (red light, traffic jam, stop sign, yaddah yaddah) just coast.
it works on the flats too, if you are not in a headwind, you can maintain speed. but the battery runs out quick (i wish i could install more batteries, because i will run my batteries to the purple bar on the flats fairly quickly).
its fun to get the best mileage. happy hypermiling. ryan in canada.
Is there a website to go to that will help you understand how to get the max out of your 2008 RX 400h?
@Mark – Here are some things to start with:
In general, you want to maximize inertia and minimize the time and total amount of pressure your right foot puts on the pedals. When you accelerate, take it a bit past your target speed, then remove your foot from the accelerator. Reapply it as gently as possible.
On the highway …
When it’s time for new tires, be sure to use low-rolling-resistance tires (LRR). It looks like the RX 400h came with either Michelin or Goodyear tires. The Michelins Energy tires are LRR, the Goodyears might not be, depending on the size. The Goodyear Eagle RS-A 235/55-18 tires are High Performance All-Season and are not LRR.