Question about Viscosity and Blending (Mobil 1)

[gerhardb]

Ok,

I've got two oils I want to mix together:

Mobil 1 10w30
Mobil 1 15w50

I'm attempting to improve the cold viscosity, as my engine burns a little oil at startup until the rings expand. I'm attempting to see if this will effect overall burning or not... but I don't want to use 50w oil in an engine designed for 30w (one the stuff warms up).

Mobil 1 10w30 has these specs:

cSt @ 40º C : 62
cSt @ 100º C: 10.0

Mobil 1 15w50 has these specs:

cSt @ 40º C : 125
cSt @ 100º C: 17.4

When mixed in a 50%-50% mixture, the new values should adverage to about:

93.5 and 12.5 respectivly.

What confuses me is that these numbers are pretty much always in SAE 30w range.

So it appears that a 40C and higher, I've created a straight 30w oil.

Since 40C is 104F, I've got no information to tell me that the cold viscosity is.

Is it really going to be 12.5?

Gerhard

 

[Dr. T]

I believe the last consensus here was that it was not possible to ascertain a straight-forward/clear-cut viscosity measurement from mixing.

My guess is you would have something along the lines of a 10W-40.

 

[TallPaul]

quote:

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Originally posted by Dr. T:
My guess is you would have something along the lines of a 10W-40.

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My guess too. A bit on the thick side of 40 also.

 

[darkdan]

Add them together, have a VOA done, request a 40 degree viscosity test be done. Now you have a better idea.