So 5,000 viscosity isn't thick? It's cold piston slap, so depending on what temperature we are talking about the "thin" oil is thicker than anything we can imagine. 5w20 is 5,000 / 9 or 555 times thicker at a given cold temp around -20/-30f then it is at operating temp. People think 0w20 is thin, it isn't even that thin at operating temp when compared to 5w20, but when it is cold the stuff is very very thick. I posted charts, can't do much more on the subject.
But I will say this, if you get cold piston slap it is worth it to try a couple different weights to see what fixes it. I'd say going even thicker then 5,000 viscosity wouldn't be what I'd do, but trying different things is worth it, especially for the guys at below -20f. As the charts show, at -20f and below is when **** gets real. Even 10 or 20 degrees warmer the viscosities are very manageable. 20w50 at 32f is more then 100 times thinner than 0w20 at -20f. 140 gear oil at 32f is over 100 times thinner then 0w20 at -20f. At -20f there is no such thing as thin oil, it's all thick thick thick.
