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Buick Rendevous Real World MPG

Karen_SKaren_S Posts: 5,092
edited June 2014 in Buick


  • I just posted this message on another thread, so it's ironic that this message board just appeared. Perhaps this will be a good way to start.

    There are so many misconceptions about gas mileage generally that I would like to attempt to clear them up. The single biggest determinant of mileage is weight. It's simple physics. It takes "x" units of energy to move "x" pounds from point A to point B. Since the energy in a gallon of gas doesn't change and the length of a mile doesn't change, the weight is the major determining factor. That's why a V-8 in the same car vs. a V-6 has worse mileage. Not because a V-8 has 8 cylinders running vs. 6 (it will run at lower RPM's than a 6 to offset the difference) but because the V-8 is physically heavier than the 6 in the same car, therefore it takes more energy (hence worse mileage) to move that heavier engine. It's the same reason why AWD or 4WD is worse than FWD. Not because four wheels are turning - that makes no difference. The difference is that in the same vehicle, AWD is simply heavier than FWD because of the extra transfer case at the rear axle. With all else being equal, a 2000 pound vehicle will have exactly double the gas mileage of a 4000 pound vehicle. It's really just as simple as that. I've never gone through the exercise, but to compare apples to apples, compare the EPA listed mileage between vehicles (despite the fact it doesn't represent real world, it's a consistent benchmark for this purpose) to the weight of those vehicles and you will find a pretty consistent ratio. Having said that, there certainly will be variations due to driving habits (heavy foot means more revs per mile), driving speed (high highway speed means more revs to overcome exponentially higher drag at significantly increased speeds), vehicle shape (the higher the coefficient of drag, the more revs required per mile), efficiency of engine (the more efficient in converting the unit of energy in gas into revs, the better the mileage), driver weight (230 pound man vs. 120 pond woman), a/c usage (higher revs to run that compressor), tire pressure (lower pressure means more tire contact with the road, hence more friction to overcome) as well as a few other things I'm sure I've missed. But the point is that these are all minor variationscompared to simply the weight of the vehicle (and contents). The biggest improvements in mileage that Detroit has made in gasoline engines over time is simply by using more aluminum and plastic vs. steel, hence making cars lighter.

    Hope that helps.
  • My 2003 AWD has averaged 21.5 MPG over its 65,000 miles. My driving is about 75% highway/25% city. This is an accurate number - I use the car for business, so I have to keep track of every mile and every gallon of gas on a spreadsheet.
  • I've got the [small] 3.4 motor with manual A/C. There are 14,000 trouble-free miles on the car. I just spent two weeks at the Jersey Shore. Going down on a 94 degree day with 4 people aboard and every inch of space filled with beach stuff, with the A/C on #4 fan setting, averaging 55 MPH in the heavy, but moving traffic, I MEASURED [DIC showed 24 MPG], at fillup, 26 MPG. The Garden State Parkway is quite flat and seems to run slightly downhill southbound. Knocking around the shore in similar weather gave 20 MPG ACTUAL. Coming home on a cool night gave 29 MPG ACTUAL. This car, kind of heavy for the size of the engine, needs a featherlight foot to avoid sub-20MPG. It'll keep up with most traffic and can hold any sane speed, but if you push things, it'll use a lot of gas doing it. Soooo, as the old Mobilgas Economy Run drivers used to say, imagine there's a fresh egg under your right foot and try not to crush it. And my current tankful of $3.29 regular inspired me to try putting the cruise control on 55, instead of 60. Saving gas means LOTS of anticipation of the road conditions ahead of you so you can do LOTS of coasting, coasting, coasting. Is that a red light or a bunch of stalled traffic in front of you a couple of blocks ahead? There's no need to speed up to reach it - just roll on [NOT at 5 MPH, though], and, chances are, you won't need much braking, either. You've just saved a few bits of gas AND it's easy on the machinery, too. Stuck on a creepy-crawly expressway? Try and let the idling engine pull you steadily at, say, 5 -10 MPH, leaving a couple of car lengths of space in front of you [you may have to close it up a bit if too many cowboys jump in front of you]. Another trick is to see just how LITTLE pressure on the gas is needed to maintain your desired speed. These Buicks make it easy with their smooth, progressive gas pedal action. Also, avoid as much as possible, any sudden changes of speed. Here's a little game to keep you alert at those boring low speeds - put the DIC on "Fuel used" and see how far you go on .1 of a gallon. Did you go 2 miles on that tenth? That's 20 MPG. 3 miles? That's 30 MPG. I once clocked 4.6 miles [that's 46MPG!]. Hey, these RDV's are compact, responsive, easy-to-maneuver SUV's, but they're NOT sports cars. They shouldn't burn a lot of gas.
  • 2002 RDV CXL. 23,500 miles so far. Getting 17.5 MPG overall. 65% Highway/35% city. Getting about 24MPG when 95% Highway, and about 16MPG when mostly city drivings. I drive the RDV for leisure/weekend only. I walk to work. I was lucky enough to find a job that is only 3 minute walking distance from my house.
  • I just bought a 2002 buick RDV AWD. I'm sweating because I seem to be hearing that it will have electrical problems. What will be my most likely mecanical issues?
  • I have owned my 02 RDV AWD since new (09/01)and it is comfortable, yet somewhat enimic in power. I bought the extended GM service and it has paid for itself. Some issues have been electrical, but I have more questions about the level of service integrity of the dealer than the vehicle. I am on my third battery, and was told that the batteries from GM have a fault in the terminals, as they crack and leak. I have had intermittant problems since the first battery was replaced. I parked the car, and it wouldn't power at all..(alot of good OnStar power to call for help!). The terminology used was the terminal was corroded, but it was actually broken and leaking. The battery was pro-rated, so I didn't pay the full price. At the time I thought the problem was just that simple. In several months, I started having electrical brown-outs, i.e. lights dimming while driving, or dimming when a load was applied to the electrical system, like the AC, or brake light switch. The radio "lost" some of it's recieving capabilities, stations local and regional aquired static (AM/FM). The dealer "fix" was resoldering the antenna connection to the glass windshield, but that didn't solve it, (They managed to scratch up the lens on the climate control screen in the process). When I took it back, they replaced the radio at no charge. The radio worked, but sometimes lost the memory settings,(You'd think this would be a clue to all that I'd said and had it in for). In four months, the 'no-start' issue happened again. They tell me the battery cable had come loose. Last month, I had 'no-start' problems again, but it would come-and-go. I found the battery loose in it's hold down, and the positive terminal wobbled. The dealer said there was no problem with the battery, just loose, retightened, but their diagnostics said that the ignition anti-theft module was bad. $200 warranty deductable cost to me. The next day, the 'no-start' condition was there, and the battery was loose. They replaced the battery and battery tray at no charge...but I suspect the ignition module is either not bad, or the current problems I've been having may have contributed to the problem, and am looking to have it tested,(any help here?). The last battery was 16 months old and had the same problem as the first two! Like most busy people, I have to loose time to chase the problem instead of having it fixed right the first time! :sick:
  • dilldill Posts: 31
    I have calculated 26.7 miles a gallon for my 3.5 litre V6 Rendezvous engine a couple times. Average around town and highway driving I get about 20.5 miles a gallon. I have a FWD w/ traction control Rendezvous, WITHOUT the AWD weight many other Rendezvous suffer from.

    I think under the circumstances I've been very pleased by the mileage considering it is a hair over 4000lbs.
  • I have a 2004 Rendezvous, with no problems till I changed the air filter. Fuel Mileage went from 26 to 15 mpg. Put in a second filter in hopes of maybe a bad one with no improvement. Any ideas would be appreciated.
  • dilldill Posts: 31
    I think it might be something that happend as a coincidence with air filter replacement and poor mileage. It,(the air filter) should have improved mileage, not hurt it like you claim it has.

    I'd get the Rendezvous down to the local Buick dealer and have them run a scan test diagnostic tool on it to check for any problems.
  • kenymkenym Posts: 405
    I live in North East Ohio and I believe they start using winter fuel additives around the end of October. My wife's 06 Corolla S was averaging 30+ since she bought it in May.
    However since the end of October her mileage has dropped to about 27 or 28 mpg. Nothing in her driving habits has changed. We still fill up at the same place. Still use 87 Octane and the car seems to run and idle the same. Just the difference in the mpg. I was told the reason for the winter fuel additives is to prevent fuel line freeze up. The gas itself wont freeze but the condensation in the lines could freeze and cause the car to stop running. I believe they remove the additives around the end of March or early April
  • gman1957gman1957 Posts: 48
    This vehicle is like having gas station near by @ all times.You never know hom much more you need to go before filling up again.It burns so much gas. I cried everytime I have to goto fillit up,cause I know in a few days I'll be back @ the station.I wish the car will just burn up and collect on the insurance and get a new vehicle.
  • motobazmotobaz Posts: 1
    2003 CX V6, 72K on the clock. We were averaging 27.3 mpg on Interstate 5 from Sacramento heading south, full load, kids dogs and luggage, AC on all the time. I set the cruise at 65. Got home to San Luis Obispo and did some town driving and still averaged out at 25 mpg for the tank. We have the Driver Info Feature which tells you your average mpg on the dash display, a nice feature. That's pretty decent for an SUV. Makes me wonder when I see some of these ads for some of the latest cars and they're bragging about getting 28 mpg. :)
  • CodeCode Posts: 1
    What is meant by FWD w/traction control?
  • about this time last year ..took rend. into service for battery lite came on downloaded patch for computer to fix....then the poor mileage started...from 25-30 hwy to 19 to 21 hwy and 18 to 21 city to 14 to 17 city. dealer replaced fuel pump ....injec cleaned and replaced....drove car with chip to record mil. and agreed .....only thing they can say is is with in paramiters.!!!!!!!!!!!!!!!!!!!!!!!...changed filter...plugs...please someone help....???? 2006 fwd 3.5 lit..basic
  • spike99spike99 Posts: 239
    If wondering...

    FWD = Front Wheel Drive (only its front wheels can spin)
    AWD = All Wheel Drive (all 4 wheels can spin).

    TCS (sometimes called TC) = Traction Control or Traction Control System means that if its special "wheel sensors" computer senses 1 wheel is spinning `too much`, it automatically applies brakes to that specific "spinning" wheel. Thus, forcing its opposite drive wheel to spin - instead of allowing its single spinning wheel to continue to spin. TCS exists on either FWD (Front Wheel Drive) or RWD (Rear Wheel Drive) vehicles. When TCS exists on all 4 wheels, its called Stability Track system. And yes, TCS on the front wheels and Stability Track across entire vehicle exists on the newer technology vehicles - like my wife's new 2009 mini-van.

    If wondering, my wife has an older technology 2003 FWD RDV (her "in town" run-about vehicle) that only has TSC on its Front Wheels. When one front wheel spins too much, that single wheel speed is forced to slowed down, thus forcing the other wheel to take more traction. From a white board perspective, vision TCS as Traction Balance System - because it balances 'drive power' delivery to the other wheel(s) - that have better traction then its single spinning wheel.

    Being a lighter weight 2003 FWD RDV (compared to more steel parts in its heavier weight AWD version), my wife's vehicle also gets good MPGs. Not as good as some better wind dynamic 3.4L vehicles (like a mini-van with 3.4L engine) but it gets much better MPGs then an AWD RDV (with 3.4L engine).

    For good understanding of TCS, surf:

    Hope this helps...

This discussion has been closed.