My local Wally-mart has started stocking Mobil-1 0w30 full synthetic oil. Has anyone used this on their LS? I have read that all toyota engines are compatible with the oil, but am curious if anyone has seen any benefits in using it, either in MPG, power, etc.

 

I've tried several grades of M1: Delvac 5w40 (commercial-grade available in 4 gal cases and 55 gal drums), 0w40 (ACEA-3, rated for BMW/Benz), and 10w30 (Walmart M1, rated ACEA-1 for GM/Chrysler). The Delvac 5w40 and 0w40 gave me consistent fuel economy numbers (best I've had). Changing to M1 10w30 caused fuel economy to DROP by 5-10%. Although I haven't had the chance yet to test the 0w40 in my new (to me) LS, I've had the same results in my '86 Toyota truck, '01 honda prelude, and '00 honda crv. ALL vehicles ran best on 0w40 and Delvac 1 5w40. The D1 is more expensive...about $28/gal vs. $6.50/qt for the 0w40. If your engine has been run on dino oil for a long time, the delvac contains more detergents to clean the varnish out of the engine. I like to use the Delvac 1 5w40 initially for 5K mi, then switch to the 0w40 for 5-7.5K mi intervals.

 

0W40 is thicker (higher viscosity) at both cold and hot temperatures. Though *one shouldn't expect much difference in real-world conditions,* the 10W-30 should provide better cold start protection (faster flow to the surfaces needing lubrication) as well as better mileage from the reduced pumping losses. If the engine was designed for 10W30, I'd stick with it instead of going to 0W40.


Mobil 1 0W-40
Viscosity, ASTM D 445
cSt @ 40º C 78.3
cSt @ 100º C 14

Mobil 1 10W-30
Viscosity, ASTM D 445
cSt @ 40º C 62
cSt @ 100º C 10.0

For comparison:
Mobil 1 5W-20
Viscosity, ASTM D 445
cSt @ 40º C 48.3
cSt @ 100º C 8.8

EDIT: Adding 0W30 specs
Mobil 1 0W-30
Viscosity, ASTM D 445
cSt @ 40ºC 63.1
cSt @ 100ºC 11.0

 

Ok, I'll bite....maybe I need another cup of coffee...but...how is 0W-xx thicker than 5W-xx or 10W-xx at cold temps, and "10W-xx should provide better cold start protection" than a 5W-xx or 0W-xx?

 

Yes, those numbers are a bit surprising, but they are Mobil's published viscosity numbers. They are all in centistokes (cSt) and of course the higher the number the "thicker" the oil. It's generally agreed that thinner oils are better for cold-start protection because they reach the critical parts more quickly and are at a more ideal viscosity to do the proper lubricating job at lower temperatures.

Looks like the 20, 30, and 40 numbers seem to be playing a big role in the low temperature viscosity as well. I don't know why the W ratings aren't in line though - the "0W" rating seems to be out of line. I'm sure there's an explanation, but I haven't looked for it. I guess it has something to do with what they call low temperature "performance" moreso that merely viscosity. <shrug>

Re: the 10W30 providing better cold-start protection, I was only saying that relative to the 0W40, not the 5W20.

EDIT: Also, please note that I was talking about these relative to 0W40 which Jim mentioned. I've now added some Mobil 1 specs for 0W30 to my original post. These really don't seem to make too much sense on the surface either -- 0W30 actually THICKER than 10W30 in the low temp viscosity testing...

 

You forgot to include the pour point. Although the KV values are higher for 0w30, the pour point (coldest temp at which fluid will run) is ~10C lower than that of 10w30. In other words, we should notice the biggest difference at lower temperatures. There are fuel efficiency gains that have been noted in other forums (i.e. BITOG), but the biggest benefit is the cold-start anti-wear benefits. It is well-known that most of the wear in engines occurs during start-up, and a thinner oil will allow for enhanced lubrication those cold mornings.

 

Here in AZ, we can nights in the 20's during the winter and days between 100-110F in the summer, so 0w40 works great for all season. 10w30 seems thin for me, but will probably work fine for you in colder climates. I find the 0w40 gives me the best fuel economy (have only tried M1 delvac 5w40, M1 10w30, M1 0w40, Shell Rotella T synthetic 5w40 [not a "true" synthetic).

I avoid using 5w30 (the normal "recommended" weight for US cars; this is because the carmakers use the lighter 5w30 during the CAFE emissions tests. By law, the manufacturer and dealer must recommend/use the same weight engine oil). On the Landcruiser/LX470, 5w30 is recommended in the US while 10w30 is recommended abroad (where people buy a new car like every 10-20 yrs).