OK to mix oil grades?

[jeansain]

I'd like to use Mobil 1 0w40 but can't find it here in Toronto. I am thinking of using a mixture of 5w30 and 15w50 (maybe 75/25 respectively). In Toronto, the coldest it gets is usually -20° Celcius (-4° F). Opinions?

TIA

[mwaller]

I don't know the answer to your particular question, but I know that some oils can be mixed and others shouldn't. You might try posing your question on one of the forums at www.bobistheoilguy.com -- those folks know a lot about oil and oil analysis. Many of them mix oils to get a desired viscosity that isn't otherwise available.
Good luck!
Mika

[manny]

Originally Posted by jeansain

I'd like to use Mobil 1 0w40 but can't find it here in Toronto.
TIA

I buy my 0 W 40 from the local M-B dealer ( Kitchener ).
It's about $ 8.50 ( CDN ) per liter.
Personally, I would not mix different weights of oil, not even the same brand.

[BigBenzWV]

I just did 5 q 15W-50 + 2.5 q 5W-30 of Mobil 1. I am in WV.

[jeansain]

Originally Posted by BigBenzWV

I just did 5 q 15W-50 + 2.5 q 5W-30 of Mobil 1. I am in WV.

Have you done this before or is it the 1st time?

[jeff-abalone]

I will not mix oil too!!

In BC, the MB dealership has Mobil 1 0W40, but I will perfer Lubro Moly 0W40.

[dakota]

There is nothing particularly wrong with mixing viscosities, despite what some have said. The problem is that you never really know what you get. You can't just average the weights and volumes and come up with the resultant viscosity. It's much more complex than that.

But one problem with your mix is that I don't think Mobil 1 5w30 is an approved oil for MB engines. As near as I can tell, in North America, the only two viscosities of Mobil 1 available and approved are 0w40 and 15w50.

While the Mobil 1 0w40 would probably be best for you in winter Canada, the 15w50 weight has a pour point of -45°C and a -37°C pumpability temperature. Easily suitable for your climate.

If there is a Wal-Mart or Costo nearby, they may have the oil you want.

[lee polowczuk]

why is Synthetic Oil so expensive... you can get regular oil on sale for a bit more than a dollar a quart. synthetic is 4x that.

[Duke2.6]

Synthetic base stocks are more expensive because they are "synthesized" in a petrochemical process rather than being distilled out of crude oil.

Also, the profit margins are higher and the industry spendings millions per year trying to convince John Q. Public that synthetic oil is "better".

In reality, synthetic is really no better than conventional mineral based motor oils assuming you follow a traditional oil change schedule. Because synthetic base stocks are more resistant to oxidation, they have longer service life and are usually accompanied with an OE oil monitoring system, but using synthetic
in an older car and changing it at the normal interval recommended for a conventional oil is a waste of money, but without a monitoring system you don't really know how long you can go.

The most critical aspect of a motor oil is the ADDITIVE PACKAGE and all API SL oils have about the same additive package regardless of base stock. Since most of these additives
are consumed during service, synthetic oil with longer change intervals is certainly NOT an improvement.

The basic advanages of synthetic are longer service life due to due slower base stock oxidation rate and a wider viscosity range with little or any VI improver, which break down with use. That's it.

Duke