No need to look back from hereI put the 0w40 Fs in this afternoon and I'm happy with the results. Its odd because it seems like the engine revs smoother despite the thicker oil. It also seemed like I was accelerating more on light throttle after TC lock up. This is particularly noticeable as TC lock up is around 36mph and I typically drive around 40mph.
Oil pressure is up, but I didn't get a good heat soak today. I think this will be a winner unless mpg tanks.
Let go over some facts. The drop in viscosity was likely attributed to meeting the latest specs. For a time, Mobil 1 held back doing that and stayed thicker. Considering all that, there is not much to worry about with a 19 year old, 190,000 mile vehicle. Either the Mobil 1 5w30HW or 0w40 will work in that car. If you don't want to go lower, then use the 0w40. If you don't want to go out of spec, then use the 5w30HW. Take your pick.It appears the viscosity of many of Mobil 1s oils have changed based on the provided viscosities on their website. For example high milage 5w30 used to be 11.7-11.9cp at 100C, but is now showing as 10.1cp.
I reached out for confirmation from Mobil 1 since this isn't an insignificant change, but got no response of value.
Anyways, now im looking for an oil recommendation for my 03 celica (1zzfe) with 190k miles. My oil pressure is fine (13psi max heat soak with ac and 55-60psi at 3krpm) with Mobil 1 5w30 HM EP, but I believe its the previous formulation with higher viscosity. I dont want to go lower with viscosity to maintain healthy pressure at idle.
I have a jug of 0w40 mobil1 fs for another vehicle, but am concerned it may be too thick at 12.9cp. Im looking to stay with Mobil 1 if ththere'a good fit since ive used Mobil 1 with the car for 88k miles. I need the oil to perform well at 100F and occasional periods down to -10F.
*Ash over 1% is not good for the DI engine owner crowd.Possible unpopular opinion here that you could mix the 5W-30 HM EP with the 0W-40 to have some sort of inexact middle ground, also because the are both Mobil 1.. however, you should be fine with either or. The 0W-40 may very well be very good. (*for your engine.)
The 1ZZ-FE 1.8L has been prone to oil consumption, something about the rings. https://tuningpro.co/the-3-most-common-toyota-1zz-fe-engine-problems/
KV100 is 13.5
HTHS a nice 3.6
Properties and Specifications
Property Grade SAE 0W-40 Total Base Number, mgKOH/g, ASTM D2896 12.5 Ash, Sulfated, mass%, ASTM D874 1.2 Flash Point, Cleveland Open Cup, °C, ASTM D92 233 Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 77 Hi-Temp Hi-Shear Viscosity @ 150 C 1x10(6) sec(-1), mPa.s, ASTM D4683 3.6 Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 13.5 Density @ 15.6 C, g/ml, ASTM D4052 0.839 Viscosity Index, ASTM D2270 180 Mini-Rotary Viscometer, Apparent Viscosity, -40 C, mPa.s, ASTM D4684 28200 Pour Point, °C, ASTM D97 -45
*Ash over 1% is not good for the DI engine owner crowd.
Concensus has not been reached.. lol..Supposedly. Not entirely convinced of that.