Mobil 1 Synthetic and MPG

[2001LC]

Does anyone have any experience or comments concerning MPG and the use of Mobil 1 synthetic ATF fluid, Oil and Lube?

Is Mobil 1 Delvac or some other brand a better way to go?

My experience is a drop in mpg after changing all lubricants to Mobil 1 synthetics. My gas mileage drop by .7 MPG average over the last 22,000 miles. This is not a lot but it adds up over time, and just as important are my LC's mechanical components wearing more or less since changing from Castrol to Mobil.


Notes:

LC100 Gas with 122,000 all stock.

After reading some of the threads here and the Mobil ATF product data sheet, I've come to the conclusion, it may be the Mobil 1 synthetic AFT that had the greats effect in my drop in efficiency (MPG).

Mobil 1 5W-30 oil is a reportedly a thinner 30W than Castrol 5W-30 so i assumed it's not part of the drop in MPG, but, Castrol advertises that they're 4 X slicker than Mobil 1; could it be?.

Mobil 1 synthetic ATF has a cST @ 100 degrees of 7.4 (currently report) and their Mobil Dexron VI ATF is at 5.83

The drop could be related to some other work done at same time like plugs, timing belt, filters or may be lazy O2 sensors, but, i think the Mobil may be the most likely culprit.

 

[Liam]

i cant believe this was even asked...first off if you're driving a 100 series you shouldnt even think about MPG, it's an oxymoron. Second, maybe your driving habits have changed a bit. Maybe you passed when you shoulda hung out behind the blue hair. Perhaps your truck is getting older and is not as efficient. I could go on and on.....personally i think you should pour sugar in your gas tank and sit back and watch your MPG skyrocket...

 

[2001LC]

i cant believe this was even asked...first off if you're driving a 100 series you shouldnt even think about MPG, it's an oxymoron..

I asked, to see who else may have noticed the same as I.

I started considering the ATF after reading (in Ih8mud. com) a specific statement; "Mobil 1 syn AFT reduced my mpg".

I'm interested in have my LC100 run at the peak performance all it's life, hopefully 500,000 or more. Proper maintenance and using the best lubes & filters are key to this.

Be assured Liam, the drop in my mpg was noticeable the day I changed to Mobil 1 synthetics. So it is unlikely (not impossible) that age suddenly cause the mpg to drop.

I see people here like Jim_Chow getting great mpg and he's using M1 Delvac oil, what AFT he's using I don't know but I do know he has been a wealth of information to me and many here and he obviously pays attention to his maintenance and how it effect his mpg.

Hopefully Jim and many others will give us some feedback on this issue.

 

[tkorade]

I changed all my fluids over to Royal Purple when the truck had 89k on it and now has over 210k and I averaged about 1 MPG over what I got with dino oil until gas changed from MTBE to ethanol additive and I lost about 2 MPG.

 

[NMuzj100]

It's theoretically possible that the ATF in your transmission had sheared so severely to a low viscosity (lowering it's lubricating ability) that the new fluid is a higher viscosity and takes a marginally higher amount of energy to pump. This is unlikely and immeasurable.

Same with any other change in MPG caused by fluids. Very small changes drowned in randomness.

 

[2001LC]

I changed all my fluids over to Royal Purple when the truck had 89k on it and now has over 210k and I averaged about 1 MPG over what I got with dino oil until gas changed from MTBE to ethanol additive and I lost about 2 MPG.

I've seen royal purple around local auto parts stores so it's fairly easy to get which is nice.

No doubt about it; the blended fuels are hard on mileage, kind of like cutting gas with water.

 

[splacek007]

I have a '00 LC - purchased used 10/2009 - changed from Castrol Syntec 5W-30 to Mobil 1 0W-40 and noticed an increase in MPGs (realize it may be the weather...from cold/snow to cold and no snow).

RE: your comment on Mobil 1 being thinner than Castrol...if you're talking about synthetics, both are thin synthetics at operating temp. (google Mobil 1 5W-30 and CST), but Castrol, to my recollection, is the thinnest at operating temp. and nears a 20W oil in viscosity.

None of my other fluids are synthetic.

 

[2001LC]

MMuzj100---it is possible, however my old fluid looked an smelt OK.

The new (M1 syn ATF) is higher a viscosity, based on Mobil data sheet.

Still i was expecting to increase mpg by going to a synthetic ATF.

What are you using?

 

[2001LC]

=RE: your comment on Mobil 1 being thinner than Castrol...if you're talking about synthetics, both are thin synthetics at operating temp. (google Mobil 1 5W-30 and CST), but Castrol, to my recollection, is the thinnest at operating temp. and nears a 20W oil in viscosity.
.

Looks like it's:

• Castrol syntec 5W-30 cST at 100 degrees C 9.7to9.9
• MI synthetic 5W-30 cSt at 100 degrees C 11.3

 

[NMuzj100]

I run Mobil1 in the engine, Amsoil ATF in the trans and PS, Amsoil 75w-90 in the diffs and TC.

 

[2001LC]

I run Mobil1 in the engine, Amsoil ATF in the trans and PS, Amsoil 75w-90 in the diffs and TC.

Why Amsoil?

 

[Sandroad]

It's worth asking questions about increased efficiency for lots of reasons. However, it's difficult to measure subtle differences in one vehicle in real-world driving for any one change (like lubricants). I couldn't find any comparison studies done on mpg and different brands of oils, other than just anecdotal marketing statements by manufacturers. However, it makes sense that lower viscosity would lead to greater efficiency; there's a lot of moving parts in a Land Cruiser drivetrain!

 

[arbetrader]

I run Mobil1 in the engine, Amsoil ATF in the trans and PS, Amsoil 75w-90 in the diffs and TC.

Hmm, I was reading my manual and it stated to use 75-90 in the diffs, and 75-80 (or something like that) in the TC (or the opposite, I can't remember) the point I'm making is that it specified two different viscosities for those applications.

I'm assuming you havent run into any issues using an oil type not recommended by the manufacturer... Can you comment on that? Thanks!

 

[2001LC]

I'm assuming you havent run into any issues using an oil type not recommended by the manufacturer... Can you comment on that? Thanks!

I'm using M1 syn 5W-30 oil, M1 syn 75W-90 in all gear boxes living in Colorado with temp range -10 to 100°F.

OM for 2001LC recommends:
Engine;
-29 to 100°F 5W-30
Differentials;
Hypoid gear oil API GL-5
Above -18°C (0°F) SAE 90
Below -18°C (0°F) SAE 80W-90 or 80W
Transfer Case;
gear oil API GL-5 or 4
SAE 75W-90

 

[2001LC]

This one paragraph on oil weight was taken from post #11 in a thread from 80-series which indicates cST may not tell the whole story:

"I have been shying away from the Mobil Xw-30 oils because they are formulated on the light side of 30 weight, almost being 20 weight. If you are looking for a Xw-30 weight, look at Redline, Amsoil (I never thought I would recommend Amsoil), or others. I truly believe for any climate that a Xw-50 oil is overkill for the Landcruiser"

https://forum.ih8mud.com/80-series-tech/79305-oil-recommendations-discussion-thread-faq.html

 

[NMuzj100]

Hmm, I was reading my manual and it stated to use 75-90 in the diffs, and 75-80 (or something like that) in the TC (or the opposite, I can't remember) the point I'm making is that it specified two different viscosities for those applications.

I'm assuming you haven't run into any issues using an oil type not recommended by the manufacturer... Can you comment on that? Thanks!

Specs are for 75w-90 in the TC and 80w-90 in the diffs.

It's hard to find 80w-90 anymore and with the newer fluids there is no disadvantage to the extra range.

When this spec was developed 80w-90 was more stable over time because it didn't require as many viscosity index improvers (VII) which break down over time. An oil like I run probably doesn't need any VIIs to operate in the 75w-90 range now because the technology is much improved. GL-5 is the key specification.

In fact the SAE standards (J306) for gear oil have tightened and a good argument could be made that a 110 weight gear oil might be better and would be in the same range as the old 90. 110 weight is within spec for the 100.

Old 90 = Viscosity 13.5-24.0 cST at 100C

New 90 = Viscosity 13.5-18.5 cST at 100C
New 110 = Viscosity 18-5-24.0 cST at 100C

SAE J306 Specifications - The Lubrizol Corporation

I sent Toyota an email several years ago asking what their current recommendation would be and they never got back to me.

Next change I may go to Amsoil Severe Gear 75W-110 in the diffs.

 

[NMuzj100]

Why Amsoil?

Because I had a good source with a storefront. I like the oils. I hate the MLM.

But with the internet you can order painlessly.

I probably spend too much time at Bob is the oil guy.

 

[bkgee]

2001LC, where are you from? As tkorade wrote, ethanol will hit your fuel economy. In the winter here, all of our vehicles suffer a 1-2 mpg hit. In the summer, fuel economy rebounds 1-2 mpg.

I just recently switched all fluids over to Mobil1 (engine, diffs, tcase, tranny, lube). but i only purchased the truck in december, and have only done one fuel economy calculation (my first drive home from AZ), i can't speak to the effect of M1 on economy.

my thoughts for my personal situation are 1) i will get another baseline fuel economy calc this summer when there is no ethanol (i want a feel good #), and i don't want to care too much about economy in this truck, but rather just be comfortable that all components are properly protected (this speaks more to your point about 500k+ miles) using spec fluids.

 

[2001LC]

Denver Colorado, and yes the winter fuel blending does drop my mpg about 1.38 mpg not taking into effect the cold of winter which is really not that bad here.

Pre changing all M1 syn lubes, with auto climate control off: Summer 16.72 Winter 15.49
Post changing all M1 syn lubes, with auto climate control off: Summer 16.12 Winter 14.74

Granted i do have very good mpg Pre and post MI syn, but I was expecting it to go up .7 not down by .7 mpg.

The ATF has only recently become a suspect, i have considered the O2's but the drop was very definitely with the change in fluids. In the interest of full disclosure i did base line the LC100, everything from timing belt to spark plugs, at the same time.

Additionally the shearing of my old fluid could have thinned the ATF and added to my Pre mpg. But that old fluid seem pretty good and was flushed by a Dealer at 60,000 miles in 2004. Not sure if they used Dexron III or VI at that time.

 

[2001LC]

I run Mobil1 in the engine, Amsoil ATF in the trans and PS, Amsoil 75w-90 in the diffs and TC.

Do you track you mpg and if so would you be willing to share that info?

You stated you like Amsoil so why not use it in the engine as-well?