Thin vs Thick Discussion, Chapter 3


Maybe we can hand out participation trophies? "Well Jimmy, you didn't get ANY of the answers right, but that's OK, we've now re-written the test so that it doesn't even make sense anymore so, you get an A+ for just showing up!"
Now head to any locker room you like for a shower 👀


Site Donor 2021
Carson City
It depends on the individual VI's of the various base fluids used. Amsoil did have the ACD and it did not have any VII's, the VI was based on the totality of the base oils used.
So based on that, can I assume that if final blend contains lower % content of improvers, because the base is already high quality (VI's) the final product will be more shear stable?
I do like that we are revisiting these topics, truthfully. Years ago the recurring theme on this website was to not fear thinner viscosity motor oils. Back then a lot of members here were on board with 5W-20 motor oils, and even those who were slightly skeptical still kept a somewhat open mind. The most common phrase back in those days regarding 5W-20 was, “use with confidence.”

Todays BITOG is much different. The tone here by many members is “screw thin oils”. IIRC, the tone here changed drastically when the evil boogeyman direct injection engines came to mass market and people started noticing fuel dilution on UOA’s. That is when the mass hate towards xW-20 oils started.

A common topic we have here today is “My new car says to use 0W-20,which brand should I use?” And most replies are all about how 0W-20 is too thin, and people start recommending to use 10W-30, 5W-40, heck a lot of people here mention to look up the owners manual in a different country and advise to use the thickest viscosity listed.

I think the most widely talked about topic these days is about the positive displacement oil pump. Generally the conversation goes like this. “My owners manual says to use 0w-20 but I have a whole bunch of 10W-30 and 10W-40 I bought on clearance. Can I use this in my engine? Oh btw, I live in Canada.” And then that
triggers the whole PD oil pump and how the PD guarantees that the right amount of oil is delivered to all parts of the engine at all times argument.

It is interesting times here to say the least. There are a handful of people here who preach their own mantra here daily, almost always against the vehicle manufacturer recommendations. My mantra is to follow the vehicle manufacturers recommendations, that has literally served me well for decades of driving and owning vehicles.

As thin as possible, as thick as necessary.

A lot of people here are going to absolutely their marbles when 0W-8 makes its way to North America.