Mixing different grades

[Matt97]

Hi Guys
Speaking to another workshop owner ,he mentioned he mixes oil grades for his own "special brew" .Any merits ? Or a monumental waste of time ? Obv his "brew' is a state secret , and would probably have to kill me if i knew it ...

 

[tgrudzin]

If his educational history is in chemical engineering, especially petroleum products, I might listen. Otherwise I have way too many other issues than to be worried about mix a 'special brew' to lubricate automotive engines. I'll trust those who reserach this for a living.

 

[dparm]

It's fine to do this if you need a special viscosity. Several of the boutique oil blenders (Motul, Red Line, and Renewable Lube, to name a few) openly advise it on their websites. In other words, I could mix a bottle of Red Line's 5w30 in with 5w40 if I want something a bit thinner than the 5w40 but thicker than the 5w40.

Technically any API-certified oil must be mixable with another API-certified oil. It may not exactly be optimal, however, since you can get additive package "clashes". I wouldn't be running out and dumping 5 different oils in there, but if I needed to top something off or thin it out a bit, it would be fine.

 

[CT8]

The strong get weak and the weak get strong. I serves no purpose , It is like trying to get a 10W-35 instead of a 10W-40.

 

[bchannell]

I just don't believe that engines are that critical on a particular viscosity. For instance, if a car calls for 5w30, I don't think it would EVER know the difference between any oil from 0w20 to xw40 assuming gasoline of course. So what would the gain be with, say, a 7.5w25 or 12.5w35?
If I was selling oil, I'd want you to mix it, put it on cold sores, change it every 2k mi, etc do whatever, as long as you buy it.

 

[Matt97]

Agree on all the above points .Apparently it is common practice with motorbike workshops around here .Really dont see the point in doing it .