0w or 5w-20 for gas mileage?

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steven88

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Someone mentioned using 5w-20 or perhaps even a 0w-20 for save gas mileage...especially if you drive real short trips...my type of driving style involves real short trips (about 5 miles) each way...occasionally i'll throw in some highway and other styles of driving...but i'm usually 75% plus, all short city driving...

the car is a 2002 Nissan Maxima vq35de engine...factory owners manual calls for 5w-30...

any comments, answers, would be appreciated! thanks
 
quote:
Originally posted by forcedtalon:
Mobil 1 is a thin 30 wt oil I would go with that.
Click to expand...
No longer true. It's more middle of the road now.

http://www.mobiloil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil1_5W-30.asp

http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil_1_Extended_Performance.asp

steven88, not that I foresee anything catastrophic happening, but I'd stick with the manufacturer's recommendations as far as viscosity, unless you're willing to do testing on your dime. SM/GF-4 oils already have mileage improvement potential built in.
 
Unless Nissan has come out (like Ford as for selected models and years etc etc) saying 0w20 and or 5w20 IS backward compatible with your particular model and year, I would stay with the lowest recommended viscosity. I understand this to be a 5w30 in your case. If I wanted to pay the extra I would step to a 0w30 Mobil One (less available and more costly where I am) I have been using Mobil One 5w30 for some years (19 years) and miles (765,000) with 15,000 mile OCI's.
smile.gif


I do use 0w20 Mobil One in a 2004 Honda Civic, but as you probably know 5w20 is the recommended viscosity. It runs like the proverbial top by the way.
 
****, thanks for the prompt replies fellas...if you say the gas mileage gains are minimal, then i'll just stick with the conventional 5w-30!
 
What part of California? According to the online 2005 Altima owner's manual I downloaded, 10W-30 would be considered an acceptable alternative at temperatures above zero degrees F. As I write this, the temperature where my indoor clock/thermometer's outdoor sensor is located in the shade of the front porch is transmitting a temperature of 106.5 degrees F. on the display. I've used 10W-30 year around in my Hyundai 2.7L V6 since its first oil change. Even so, I consistently achieve 30+ mpg highway and 23+ mpg city. Even if I gained a whole unit mpg improvement with the use of 5W-30, I doubt I'd bother switching over.
 
quote:
Originally posted by ruking77:
I do use 0w20 Mobil One in a 2004 Honda Civic, but as you probably know 5w20 is the recommended viscosity. It runs like the proverbial top by the way.
Click to expand...
Me too, in a 2001. I know everyone thinks I'm crazy but fuel mileage has literally gone WAY up over the course of 11 tanks of gas. Like 3 miles a gallon. I know it shouldn't but my real-world highway driving has proven so since June 1st. I used to use Amsoil's 0w30.
 
quote:
Originally posted by Chris Meutsch:

quote:
Originally posted by ruking77:
I do use 0w20 Mobil One in a 2004 Honda Civic, but as you probably know 5w20 is the recommended viscosity. It runs like the proverbial top by the way.
Click to expand...
Me too, in a 2001. I know everyone thinks I'm crazy but fuel mileage has literally gone WAY up over the course of 11 tanks of gas. Like 3 miles a gallon. I know it shouldn't but my real-world highway driving has proven so since June 1st. I used to use Amsoil's 0w30.
Click to expand...
My mph is between 38-42 in a plain jane daily commute.
 
You will not automatically gain gas mileage by using a low viscosity oil. The idea is to use an oil that completely fills the space between surface (A) and surface (B). The Nissan VQ V6 has been determined to prefer a thicker oil by others on this site. Therefore it is highly probable that that you will have the best gas mileage using a 10W-40.
 
quote:
Thankfully Nissan cares about owners who want to keep their cars for long periods of time. In order to do that, you have to have protection. 5W-20 is thinner than 5W-30 so therefore there is less protection.
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confused.gif


Does anyone care to comment on this statement?

Am I really providing less protection by putting in 5W20 in my new Honda Civic?
 
Not really think about it, high reving 4 cyl with lighter drivetrain components. May or may not benfit from a thicker oil when hot. May also need a greater flow volume to wick away heat from vital oil lubed components as long as it doesn't overwhelm the actual capacity for the engine to do so.

I am still on the fence with 5w20 oils but can see a use for them...some all aluminum compressors I came across call for a 10-20w oil where the heavier cast iron ones want a 30 weight at least.
 
Is 5W-20 the end all/be all ticket to excellent fuel economy?
confused.gif
I welcome anyone's comment to that question. As for the thread starter: Does your owner's manual allow for 10W-40?
 
Clyde65 = most REAL fuel economy gains are during warm up ..about the first 15-20 minutes of driving. They taper off as you get deeper and deeper into the 15-20 minute time frame. Go and look at the 40C spec's for your oil. That's the visc @ 100F+/-. Then you see what weight oil you're churning at start up. Compare it to 20 weight. Now since the vast majority of commuters are heavily weighted in the "mostly warm up" state ...the vast majority will reduce parasitic losses in proportion to the differences in visc.

Since the OP's primary service is 5 miles ...he will probably be above a 70 weight with a 10w-40 for the full duration of his trip. With a 5w-20 ..he may be in the 40 range. The highway service should be fine at the flow rates that this use requires ..even if it "likes" a heavier oil.


This is something that no one seems to figure out. For most of us who are on a 300 miles run ...the difference between a 50 weight and a 20 weight would probably be barely detectible in vehicles over a certain size (due to typical highway speeds and aero loads) ..but the savings during the short trip usage can be substantial.

That is, what may be anywhere from 0.5%-2% on long mileage usage ..may be up to 20% on short trip usage depending on how much parasitic losses contribute to your short trip fuel economy. The difference between the 100F and 100C visc is probably 10X. In the case of a 40 vs. 20 ..it's probably 15X the difference.

For Mobil Clean:
5w-20
40C: 47
100C: 8.3
10w-40
40C: 97
100C: 14.0

Difference at 100C 5.7 CST
Difference at 40C..50 CST ..or approx 10X the difference at full temp

..but it's DOUBLE the visc @ 100F

Whatever hp you're using with a 20 weight @ 100F ...you're using over TWICE as much with a 40 weight.
 
quote:
Originally posted by Clyde65:
Is 5W-20 the end all/be all ticket to excellent fuel economy?
Click to expand...
Not even close. We run 0w40 in our Odyssey and get 23mpg in suburban use. The fact is that driving technique VASTLY overshadows mpg gains from a lower viscosity.

Watching everybody stomp on the gas and jam on thier brakes, I know that even Redline 2W isn't going to improve thier mpg very much.
 
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