Originally Posted by edyvw
Quote
The cold-engine viscosity is not determined by the x in xW-y. It's determined by the y in xW-y and viscosity index. x in xW-y determines the crankability (CCS) and pumpability (MRV) at very low temperatures, not the operational low-shear or high-shear viscosity at most temperatures.
For example:
Mobil 1 15W-50 KV100, KV40, and KV20 = 18.0, 125, and 342 cSt, respectively.
Castrol 10W-60 KV100, KV40, and KV20 = 22.7, 160, and 436 cSt, respectively.
Mobil 1 FS 0W-40 KV100, KV40, and KV20 = 12.9, 70.8, and 170 cSt, respectively.
TGMO 0W-20 (© 2015 reformulation) KV100, KV40, and KV20 = 8.4, 35.2, and 72.8 cSt, respectively.
As you see, a 15W-xx can be thinner than a 10W-xx when cold. a 0W-xx can be several times thinner than another 0W-xx when cold.
No, I didn't recommend TGMO, which is a fairly thin oil. Nevertheless, I don't think it will do any worse if not better in this poorly designed engine than the recommended 10W-60.
Note that the bearings and oil pressure are both governed by the high-shear, not kinematic, viscosity, regardless of the temperature.
So, some are saying that the wear happens because people don't follow the old "Do not race a cold engine" caution. Perhaps, but then this caution applies to all oils and engines. Also, psychologically, this conjecture is buried in their 10W-60 use (We're using a very thick oil and we should be easy on the pedal when the engine is cold.)
You seriously do not have any idea that people here know that. I do not understand point of your post. What you trying to say? That you search internet good?
Regardless whether oil is 0W or 10W, cold engine is cold engine, and according to some theory that is culprit. Only recommended oil is 10W60. Let's say there is good reason for that. You will not solve this puzzle by reading stuff on internet which in many cases is inaccurate.
And TGMO? Poorly designed engine? Is that why Toyota buys engines from BMW? Because they cannot design engine?
Stick to Corolla.
Well. Toyota did buy some diesels from BMW to use in there European market. But those engines is with out a doubt the worst pile of [censored] ever to be dropped in a Toyota engine bay. The number of common problems with those engines are massive compared to what the typical Toyota owner is used to.