Originally Posted By: Ken2
Originally Posted By: 7TFord
I'm usng Motul's Eco-nergy 5/30...
http://www.gprparts.com/brands/motul/motul8123.asp
...in my 4.7L 4Runner because it calls for an "SL" rating.
This is meaningless. SL has been superceded by SM. If your manual was re-written today, it would call for SM oil--and that is exactly what the 4.7 engine of today uses and what the dealership would put into your engine.
HTHS viscosity is a very different measure than the kinematic viscosity measures in centiStokes. HTHS gives a much more realistic measure of what happens to the oil in the engine. Kinematic viscosity is merely the time it takes a quantity of the oil at the specified temperature to flow through a certain orifice. With the modern viscosity index improvers and other additives, this is not the best measure of how the oil reacts in service.
In some cases the engine maker will specify an oil for low pumping and friction losses inside the engine to save fuel which is also the right oil to protect the engine. This is what we see in the trend to lower viscosities including lower HTHS viscosities. A higher vis oil might give longer engine life, or the engine life with the lower vis oils might be as long as the life of the rest of the vehicle.
I agree. The manual for our 08 Yaris Sedan calls for an SM oil but oddly enough the filler cap still denotes an SL standard. I guess they don't make new caps as often as they print manuals. The bottom line I guess is I chose the Motul product for my 4Runner as it is a quality lubricant and isn't likely to detonate my Lexus born 4.7 motor low or high HTHS, and if I get a few more mpg's so be it. I certainly don't want a 15/50 in there!
I'm still curious though as to the statement at the above link?
"These oils may be unsuitable for use in some engines"
Curious as to the definition of "unsuitable"? There are actually engines that these oils will harm? There is no mention in my 06 4Runner manual or the manual for the 08 regarding HTHS and I'm pretty sure there isn't even anything on the Motul containers I have either.