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Used Oil = less MPG... Any Proof?!? #4689168
03/08/18 09:15 PM
03/08/18 09:15 PM
Joined: Dec 2016
Posts: 7,199
Waco, TX
Linctex Offline OP
Linctex  Offline OP
Joined: Dec 2016
Posts: 7,199
Waco, TX
I have about 9,300 miles on my OCI. (Frankenbrew, prob close to 5W-30-ish)

I filled today & calculated 18.1 MPG, about .2 mpg better than my "running average" of 17.9.

Has anyone actually done any REAL studies that says used oil = less MPG?
The motor oil companies all "say so".... but I don't think I've seen anything legit.


"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689179
03/08/18 09:24 PM
03/08/18 09:24 PM
Joined: Jan 2017
Posts: 2,037
VW Fanboy Island
maxdustington Offline
maxdustington  Offline
Joined: Jan 2017
Posts: 2,037
VW Fanboy Island
I read in Car Craft way back in the day that a fresh synth OC was worth 10 hp. Drag racers in restricted classes would change their oil after a few passes to maintain the effect.

I know that is not really proof, but this was during the early-mid 2000s when synthetic oil just started to become mainstream.


03 Jetta AWP/09A 205k kms
Edge 0W40 + Mann 719/30
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689185
03/08/18 09:26 PM
03/08/18 09:26 PM
Joined: Sep 2014
Posts: 2,179
US-WA
Dyusik Offline
Dyusik  Offline
Joined: Sep 2014
Posts: 2,179
US-WA
The only reason I would believe that claim is when oxidation pushes the viscosity WAY up. That would take, what? 15? 20? 30k miles? Even at that, what are we talking about, 0.3%?


95 Cherokee 190K DELO 10W30, XG8
07 IS250 103K Napa 10w30, FULL
04 YZF-R1 19K DELO 15w40, XG7317
99 HD XL1200S 21K VR1 20w50, NG1515
14 RX450h 35k PP MIX, NG7047
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689211
03/08/18 10:00 PM
03/08/18 10:00 PM
Joined: Mar 2016
Posts: 1,580
Toronto
PeterPolyol Offline
PeterPolyol  Offline
Joined: Mar 2016
Posts: 1,580
Toronto
Agree. The marketing guys are extrapolating oxidative thickening to a concept more palatable and arousing to the consumer, Horsepower.


Scambling for solutions is a hopelessly futile endeavour and potentially dangerous, without first coming to a solid, personal understanding of the problem. Beware riding the ideological hobby horse.
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689214
03/08/18 10:02 PM
03/08/18 10:02 PM
Joined: Oct 2009
Posts: 3,529
Wet side WA
JohnnyJohnson Online content
JohnnyJohnson  Online Content
Joined: Oct 2009
Posts: 3,529
Wet side WA
I have run tests with my Duramax and Toyota Corolla with oils that claim to increase mileage. You could never prove it by me. A five to eight PSI change in tire pressure did thought in fact a couple MPG!

Last edited by JohnnyJohnson; 03/08/18 10:10 PM.

2004 Corolla 126884
Out: VML 5w-30 TG4967 OCI 5007 Miles
In: EDGE EP 5W-30 Bosch 3311 122537 7-18-18
2006 Duramax 74478
Out: T6 5W-40 M1-303
In: T6 5W-40 XG9100 73705 4-22-18
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689224
03/08/18 10:22 PM
03/08/18 10:22 PM
Joined: Mar 2015
Posts: 5,433
Virginia
bbhero Offline
bbhero  Offline
Joined: Mar 2015
Posts: 5,433
Virginia
I have done 40 plus runs with checking my gas mileage new car old oil.

New oil= 29.4 to 29.8

Old oil= 28.4 to 28.8

And it was remarkably consistent. Every time past 4k miles running Pennzoil Ultra or Castrol gold bottle 5w30. Or around 2700 miles for other group 3 oils. Same road on Rte 5.

Doing something once, twice or three times is not meaningful to me. But having done it 40 plus times... It is and was shockingly consistent fall off. Pretty meaningful to me due to how many times I did it and how consistent it was as well.

Last edited by bbhero; 03/08/18 10:23 PM.

Nissan Altima 3.5 Coupe
Mobil Super 5w30 Wix 57356
"Treat your family like your friends and treat your friends like your family."
Re: Used Oil = less MPG... Any Proof?!? [Re: JohnnyJohnson] #4689232
03/08/18 10:32 PM
03/08/18 10:32 PM
Joined: Dec 2016
Posts: 7,199
Waco, TX
Linctex Offline OP
Linctex  Offline OP
Joined: Dec 2016
Posts: 7,199
Waco, TX
Originally Posted By: JohnnyJohnson
A five to eight PSI change in tire pressure did thought in fact a couple MPG!


Yes, the difference in heavy cars/light trucks is VERY pronounced.
The change seems smaller with lighter cars.


"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689233
03/08/18 10:34 PM
03/08/18 10:34 PM
Joined: Dec 2016
Posts: 7,199
Waco, TX
Linctex Offline OP
Linctex  Offline OP
Joined: Dec 2016
Posts: 7,199
Waco, TX
Originally Posted By: bbhero

New oil= 29.4 to 29.8
Old oil= 28.4 to 28.8
And it was remarkably consistent. Every time past 4k miles


How odd.....
I would not have guessed that.
4,000 mile oil is usually still in tip-top shape. (ESPECIALLY Pennz U or Castrol GB)


"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689257
03/08/18 11:28 PM
03/08/18 11:28 PM
Joined: Oct 2012
Posts: 4,825
Taiwan
Ducked Offline
Ducked  Offline
Joined: Oct 2012
Posts: 4,825
Taiwan
Shear, thermal cracking and fuel dilution would be expected to go the other way.

This implies that, for a lot of oils over quite a high proportion of an OCI, any effects might cancel out, until you got to fairly terminal oxidative thickening.

Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689291
03/09/18 01:24 AM
03/09/18 01:24 AM
Joined: Mar 2015
Posts: 5,433
Virginia
bbhero Offline
bbhero  Offline
Joined: Mar 2015
Posts: 5,433
Virginia
Seriously Linctex.

Strange but a consistent pattern in both my Ford Fusion and my Nissan Altima 3.5. An interesting note is that Pennzoil Ultra and Castrol gold bottle both held up maximum gas mileage longer than any other oil I ran in either car.

All of the other oils started dropping between 2500-2800 miles.


Nissan Altima 3.5 Coupe
Mobil Super 5w30 Wix 57356
"Treat your family like your friends and treat your friends like your family."
Re: Used Oil = less MPG... Any Proof?!? [Re: maxdustington] #4689293
03/09/18 01:31 AM
03/09/18 01:31 AM
Joined: Jan 2017
Posts: 490
Virginia
Hemispheres Offline
Hemispheres  Offline
Joined: Jan 2017
Posts: 490
Virginia
Originally Posted By: maxdustington
I read in Car Craft way back in the day that a fresh synth OC was worth 10 hp. Drag racers in restricted classes would change their oil after a few passes to maintain the effect.

I know that is not really proof, but this was during the early-mid 2000s when synthetic oil just started to become mainstream.


I can vouch. For the 1st 500 miles after changing my oil the engine is more responsive and pulls harder. The first couple fill ups after oil changes are pretty poor mpg wise as a result.


2009 Buick LaCrosse (3800 Series III) - 137,000 miles.
PZ Plat HM/Mobil 1 HM
Bosch/Purolator/Mobil filters
Re: Used Oil = less MPG... Any Proof?!? [Re: bbhero] #4689384
03/09/18 08:13 AM
03/09/18 08:13 AM
Joined: Sep 2014
Posts: 2,179
US-WA
Dyusik Offline
Dyusik  Offline
Joined: Sep 2014
Posts: 2,179
US-WA
Originally Posted By: bbhero
I have done 40 plus runs with checking my gas mileage new car old oil.

New oil= 29.4 to 29.8

Old oil= 28.4 to 28.8

And it was remarkably consistent. Every time past 4k miles running Pennzoil Ultra or Castrol gold bottle 5w30. Or around 2700 miles for other group 3 oils. Same road on Rte 5.

Doing something once, twice or three times is not meaningful to me. But having done it 40 plus times... It is and was shockingly consistent fall off. Pretty meaningful to me due to how many times I did it and how consistent it was as well.

Change oil in winter/spring by chance?

Last edited by Dyusik; 03/09/18 08:15 AM.

95 Cherokee 190K DELO 10W30, XG8
07 IS250 103K Napa 10w30, FULL
04 YZF-R1 19K DELO 15w40, XG7317
99 HD XL1200S 21K VR1 20w50, NG1515
14 RX450h 35k PP MIX, NG7047
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689462
03/09/18 09:55 AM
03/09/18 09:55 AM
Joined: Oct 2014
Posts: 12,593
Idaho
CT8 Offline
CT8  Offline
Joined: Oct 2014
Posts: 12,593
Idaho
Clean oil is happy oil.


2015 Ford F150 2.7
2018 Ford F350 6.2
Re: Used Oil = less MPG... Any Proof?!? [Re: CT8] #4689479
03/09/18 10:15 AM
03/09/18 10:15 AM
Joined: Sep 2015
Posts: 3,954
Connecticut
69GTX Offline
69GTX  Offline
Joined: Sep 2015
Posts: 3,954
Connecticut
Ensure that the tests are all done at equal ambient temperatures. The density of air can vary up to 10-13% in summer vs winter in cold weather states.


----------------

2001 Lincoln Cont 4.6L DOHC/ 39K mi / QS HM 5w30 / FUG XG2
1999 Camaro SS M6 /19K /Mobil 1 0w40 /Fram UG /GM MTL-ATF
1969 Ply GTX/RRs
Re: Used Oil = less MPG... Any Proof?!? [Re: Linctex] #4689480
03/09/18 10:16 AM
03/09/18 10:16 AM
Joined: Nov 2008
Posts: 12,761
NH
supton Offline
supton  Offline
Joined: Nov 2008
Posts: 12,761
NH
Originally Posted By: Linctex
Originally Posted By: bbhero

New oil= 29.4 to 29.8
Old oil= 28.4 to 28.8
And it was remarkably consistent. Every time past 4k miles


How odd.....
I would not have guessed that.
4,000 mile oil is usually still in tip-top shape. (ESPECIALLY Pennz U or Castrol GB)


I believe Chris142 has indicated that, in order to pass CA smog, they often recommend an oil change. The new oil is better able to absorb blowby it seems, and thus engine out emissions is improved. If so, then I wonder: perhaps once the oil "loads up" with these lighter compounds, and no longer absorbs it, then any and all blowby is simply rerouted back into the engine. But this blowby now acts as "negative BTU's", or causes ignition timing to be pulled slightly, something, which causes a net loss of power (and thus an increase in fuel consumption). The oil could very well be still very good at what it does primarily (lubricate stuff).


2011 Toyota Camry, base, 2.5L/6MT, 170k, hers
2010 Toyota Tundra DC, 4.6L/6AT, 144k, ours
1999 Toyota Camry LE, 2.2L/4AT, 195k, his
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