Will GC increase or decrease gas mileage?

blupupher

Site Donor 2021
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Location
Katy, Republic of Texas
It will make little if any difference. If you are currently running a very thick 50 weight or a very light 20 weight, you may see a little more difference. I think all the oil makeers say that the oil itself is only a total 2-3% factor in fuel economy, so a change in viscosity would only be a portion of that.
 
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5,785
Location
Dixie
Compared to using an API/SM or ILSAC/GF-4 formulation in the SAE 5w-30 grade, it will probably reduce your fuel efficiency by a very small amount. We're talking 1%-2% here at most .... The sole reason is that the HT/HS viscosity of this oil is 3.6 Cp, compared to 3.0-3.2 Cp for most other 5w-30 grades. On the plus side the GC/0w-30 provides the best valve train protection of any SAE 0w-30 or 0w-40 you can get at that price point. Tooslick
 

daemonite

Thread starter
Messages
494
Location
Fremont, CA
Well the GC has been inside my Scion tC for about a week, haven't had much driving time as of late to monitor how my gas mileage is. Although I did fill up recently with Arco which usually knocks my gas mileage down a good 2 or 3mpg
 
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40,604
Location
Great Lakes
quote:
Originally posted by wavinwayne: I recently switched my '00 VW 1.8T from M1 0w40 to GC. I have not noticed any difference in gas mileage.
Same here.
 

JHZR2

Staff member
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45,952
Location
New Jersey
I log and calculate every tank. In my truck, I switched from Castrol start-up 5w-30 to GC 0w-30. The mileage has been consistent and the same. JMH
 
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253
Location
Boston
YMMV, but in my 2002 Subaru Impreza TS M1 0W-30 (API SL) 24.5 MPG average GC 0W-30 (API SL) 22.5 MPG average Mine is only one data point on the information superhighway... feel free to add your own data point!
 
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453
Location
stanwood, wash.
have run 4 10000mile oil samples so far. Two with M1-one Amsoil-and the last with GC. I average 42/45mpg. Toward the end of the Amsoil and the GC 10000mile run my milage had taken a noticable drop of 1to2+mpg only to be back to normal as soon as the oil change was made. Both the Amsoil and GC had thickend after the 10000mile run where the M1 had not. But the M1 showed a larger amount of iron where the Amsoil and the GC had not. 98 Suzuki Swift 1.3l
 

2x

Messages
67
Location
Massachusetts
I dropped 4-5 mpg in comparison to M1 0w-30 or 5w-30. From my readings on this board the people who do the best with this oil are those with American cars or German cars. The ones who report most of the MPG drops are 4 cylinder Japanese makes.
 

blupupher

Site Donor 2021
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Location
Katy, Republic of Texas
Well, I noticed a drop in mileage with Mobil DC from the dealer for the 1st oil change. I then went to GC and had no change in mileage, but it was also the same time winter gas was coming out. I am now with RP 10w-30 and still getting the same mileage.
 

Patman

Staff member
Messages
21,993
Location
Oakville, Ontario
I noticed no change in mileage in my wife's Civic when I went from Mobil 1 Trisynthetic to Royal Purple 5w30 to GC 0w30. All three oils showed identical MPG numbers. She only gets about 23 MPG (city driving, combined with her lead foot) [Smile]
 

MMX

Messages
33
Location
Ontario, Canada
Ditto. I noticed no change in mileage when I went from Mobil 1 5W30/10W10 to GC, and from GC to 0W40 Lubro Moly (now) in my 4-cylinder B16A2 Civic. [Smile]
 
quote:
Originally posted by JHZR2: I log and calculate every tank. In my truck, I switched from Castrol start-up 5w-30 to GC 0w-30. The mileage has been consistent and the same. JMH
[Off Topic!] How did that Castrol Start-up do in your truck? Just curious because I felt it was a marketing gimmick from jump..
 
Messages
1,462
Location
MD
quote:
Originally posted by Patman: I noticed no change in mileage in my wife's Civic when I went from Mobil 1 Trisynthetic to Royal Purple 5w30 to GC 0w30. All three oils showed identical MPG numbers. She only gets about 23 MPG (city driving, combined with her lead foot) [Smile]
[Off Topic!] Patman,every morning on the way in to work someone passes me like a complete maniac,racing from light to light in mulberry Civic.He's either slamming the gas or the brakes LOL. One day i'm gonna blow the doors off of him [Wink] .
 
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