Thinner than 90 weight gear oil at 20F.
Drain your Subaru and fill it with 80w90, wait until its -20F and start it.
Engines are built to certain tolerances that require certain weight oils to properly lubricate engine components in tight little spaces. Some Hondas take 0w20, my S2000 requires 10w30. It all depends what the little Japanese engineer decided would work the best.
If your car sits for a day and you start it, the oil has to circulate through the oil pump and reach those areas. If the oil is too thick upon start up then it wont flow properly possibly creating unnecessary wear on those engine components. Thus, you would want a thinner oil when starting to quickly protect those areas and once the engine has reached operating temperature you would want a slightly thicker oil for better protection against heat and I imagine as engine tolerances increase in size.
Vlad, as TT said, the viscosity measurement for the first and second number are completely different. Meaning that what makes sense for the first number, will not make the same sense for the second number.
5 weight in the first number measurement is not the same as 5 weight in the second number measurement.
I hope that makes sense, it makes sense in my head
Regardless, your fighting with the wrong people, everything everyone has told you is the facts, you should be bitching at the guy who thought of the system not the people who understand it :lol
If a fluid measures 5 at x temp, it will always be more fluid then anything that measure 10 at x temp. Same speed of flow for two different fluids got the same rating number regardless of what temperature they were at. Temp was simply noted for reference.
Look at the chart posted earlier and you will see 20w at 32 has the same cst as 20 SAE at 210.
Which means 20w = 20. Stop making up your own rules. They are directly comparable.
Show me where it says that viscosities are not comparable unless they are at the same temperature.
The viscosity of a fluid is highly temperature dependent and for either dynamic or kinematic viscosity to be meaningful, the reference temperature must be quoted.
Cold honey VS warm honey will clearly be different so you record their temps at the time of viscosity measurement.
What the bafoons are saying is that cold honey value is incomparable to warm :banghead
Edit: so do we all finally agree that cold viscosity numbers are directly comparable to same fluid warm viscosity numbers or you still going to play ignorant?
You can’t compare them to each other when on the same bottle (which you’re trying to do), but you can compare the non W number and the W number on the same bottle to the SAE scale-
Again, for the 10000th time, 5w30 oil flows like a SAE 5 at low temps (hence the w), and like a SAE 30 at high temps (hence leaving off of the w).
If you cannot grasp this concept soon, I’m going to start to question your ability to run this forum. This is honestly one of the silliest arguments that I’ve seen in the history of the Internet.
I’m not “going and reading anything”. Do you honestly think you’re correct that the SAE,ILSAC, and all of the major oil manufactures have unknowingly incorrectly labeled oil since the creation of multigrade oil?!?
You’re wrong and you’re being a troll on your own forum. Why not try to save some face, admit that you’re wrong, and move on?
