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Ford Crown Victoria/Mercury Grand Marquis General Maintenance

I have a 2000 Grand Marquise with 50.234 miles. I see the 2005 and 2006 Grand Marquise call for 5w-20 motor oil. It’s the same motor as in my 2000 question is can I use 5w-20 in my 2000 Grand Marquise.
I currently use mobile full synthetic 5-30.

Any thoughts
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Comments

  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,321
    Mobil 1 5-30 is great. If you ever get to 120,000 miles, you may need to mix half 5-30 and half 20/50 to get 12.5/40 which is working just fine in my 94 Town Car & 95 T Bird. ;)
  • marsha7marsha7 Posts: 3,666
    iusecad: thanks

    tritium: my 04 Crown Vic 4.6L calls for 5W-20, but I use Castrol Synthetic 5W-30, same as I use in my 04 Ram Hemi...I fail to use how a 30 weight when hot can hurt the engine in place of the reco 20 weight...besides, is the actual difference even noticeable from 20 to 30 weight???...maybe in the cold tundra of Alaska/North Dakota and Montana, but in Georgia winters, where the temp spends two weeks below freezing and we call that "cold?"
  • jsylvesterjsylvester Posts: 572
    I'm going with 5w30 synthetic in my Grand Marquis - I use 5w20 only in the winter, at best. It is just too thin for my tastes.
  • johnclineiijohnclineii Posts: 2,287
    Why are you tasting oil? :P
  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,321
    Naturally, to ascertain if the engine is diabetic! ;)
  • jsylvesterjsylvester Posts: 572
    Reminds me of one of those low carb beers - speaking of which, having a beer may not be a bad idea.
  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,321
    "Alls well that ends (with a)swill." ;)
  • fscaranofscarano Posts: 44
    I drive a 2000 Grand Marquis 56-thousand miles. I currently average 24-26 MPG Highway. Tires at 34 PSI Mobil 1 5w-20 synthetic, any other ideas how to squeeze a few more extra MPG?

    Is Ford's 100.000 mile tune up good should I do sooner?
  • euphoniumeuphonium Great Northwest, West of the Cascades.Posts: 3,321
    Weight is a factor. What you are hauling around in the trunk that doesn't need to be there should be removed. That goes for the back seat area as well. ;)
  • fscaranofscarano Posts: 44
    Trunk 2 soft ball gloves. 2 Motorcraft oil filters. And of course me in the front seat.
  • turbo301turbo301 Posts: 73
    If you're doing mostly highway driving, up your tire pressure to 37 psi at all corners.

    I'd say that MPG isn't too bad, though, for a 6 year old car.
  • fscaranofscarano Posts: 44
    Turbo301,

    Why 37psi for more fuel economy?
  • g45g45 Posts: 17
    More air increases a tire's rolling diameter, hence the amount of travel per tire revolution. This enhances gas mileage.

    It also mitigates in favor of wearing out the rear tires at their centers. So you had better be sure you are saving more on gas than it is costing you extra for tires.
  • bobw3bobw3 Posts: 2,997
    More air increases a tire's rolling diameter, hence the amount of travel per tire revolution. This enhances gas mileage.

    That would mean that you could put on larger tires and get better mpg?? I believe the reason for better mpg with increasing tire pressure is that it reduces friction. Just like if you were driving with tires more narrow. Just don't keep the pressure that high if it's snowing, because then you'll want more traction.
  • g45g45 Posts: 17
    "That would mean that you could put on larger tires and get better mpg?? I believe the reason for better mpg with increasing tire pressure is that it reduces friction. Just like if you were driving with tires more narrow. Just don't keep the pressure that high if it's snowing, because then you'll want more traction."

    Excellent analysis. I wish I'd thought of that!

    First, though, re your tire diameter remark:

    Yes, of course larger tires will result in better gas mileage because, once again, rolling diameter is increased. This is equivalent to changing to a higher rear-end ratio. Done within the transmission this is called "overdrive". All three approaches yield more forward travel of the vehicle per engine revolution.

    But your idea is cooler, more subtle, and I agree with it.

    One can ask, for a fixed final drive ratio, including tire diameter:

    With which tires will I get better mileage, those absorbing energy through added flex or those flexing less and running "harder"? I agree with you that absorbtion of energy by the softer tires, even when rolling diameters are meticulously held constant, will result in a larger throttle opening at the same vehicle velocity. It's because that lost energy, quite literally, has to come from somewhere. It WILL come from the engine and reduce mileage, just as you pointed out.

    So it isn't just the rolling diameter which contributes to better mileage, but the reduction in rolling resistance as well, when the tires are run at greater pressure.
  • fscaranofscarano Posts: 44
    :surprise:
  • bobw3bobw3 Posts: 2,997
    I guess I'm still slightly confused on the larger diameter creating better gas mileage. You said it's the same as having a higher gear in the transmission, but if you had an automatic transmission for example, putting larger tires on the car would require more power from the engine to make one rotation of the tire, so the car would remain in a lower gear longer to provide. So I still don't see what would be gained in mpg by just adding a larger tire size. To me it seems like increasing tire size would would require more gas to be used to maintain the same speed.

    Here's a quote:
    http://autos.msn.com/Advice/Article.aspx?contentid=4018909
    "Even larger tires can have an effect. A tire with a larger "footprint" on the road that doesn't have a special rubber compound designed to improve fuel economy has more rolling resistance than a comparable smaller tire, and this can lower fuel economy"
  • turbo301turbo301 Posts: 73
    There's always a trade-off between fuel economy and performance when it comes to tires. That "larger footprint" of a more agressive tire kills your fuel economy, but the same frictional forces that do that are what allow you to corner better.

    A larger tire diameter effectively translates the rotation of the hub to a higher velocity at the outside. Just look at a record or CD as it's turning: the hub is fairly slow, but the circumference is moving very quickly. v = r*w, where "v" is the linear velocity (tangential to the circumference), "r" is the radius of the circle, and "w" is the angular velocity. Thus, the bigger the radius, the larger the linear velocity, which translates into a faster-moving car. Or, you could look at it from the other way: the less fast the hub has to turn in order to maintain a given speed, and thus the less fast the engine has to turn, thereby saving fuel.

    That's my theory, anyway ;)
  • bobw3bobw3 Posts: 2,997
    I guess I'll stop because my comments are becoming "circular" but when you say, "the less fast the hub has to turn in order to maintain a given speed, and thus the less fast the engine has to turn, thereby saving fuel." but the transmission is in between the tires and engine, so you'll still need more power in the engine to maintain the higher speed, regardless of whether or not the higher speed

    Using your CD example, if you put your hand on the edge of the CD when it's spinning (like the tires on the road), it's easy to stop the CD from moving, as compared to touching the inner wheel moving. So for a given CD motor, you can stop it easier on the edge then close to the center. To make it so when you pressed against the edge of the CD, the CD kept moving, you'd need a more powerful motor, which is the same as needing more power coming from an engine, which needs more gas to get that power.

    Anyway, I'm probably wrong.
  • turbo301turbo301 Posts: 73
    You can stop a CD by the edge better than in the middle because the torque you're applying is larger: torque is the product of the force times the radius, so the further out you grab, the higher the torque you apply (that's why torque wrenches have such long handles).

    However, in the case of a car, remember that it takes almost no power to keep a car moving - maybe only 15 hp or so to maintain a given highway speed. This is how the whole V8-6-4, "Multi Displacement System", etc. are able to be so effective at saving fuel. For us Panther folks who run on all 8, all the time, there are gobs of excess power that our motors make at highway speed that is virtually useless; thus, even though it may take more energy to get the outer radius of large tires spinning against the friction of the road, the engine doesn't need to spin any higher to transfer its already-excess power to the wheels. I think that that makes sense, anyway :). My background is electrical engineering, so it's been a while since I've used any mechanical stuff!
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