Mixing Oils?

[Garak]

Originally Posted By: tig1
M1 does not recommend mixing different oils. Here is there link.

In fairness, we should look at XOM's motivation for this (outside of selling more synthetic oil). They have some pretty impressive warranties on their oils. It's 10,000 miles for M1 and 15,000 for Mobil 1 Extended Performance. I suspect it's 0 miles for a mix of M1 and "something else." We know they're not completely against mixing, at least mixes within their own product lines, suitably chosen, and for a purpose.

 

[CT8]

Originally Posted By: fdcg27
Originally Posted By: CT8
passenger car motor oils can be mixed by design. You will fortify the weaker oils or dilute the stronger oils. There is not a whole lot of difference between them as far as mixing goes.


So we should ignore what a twelve year member who's an engineer posts and take your word for it?
The real concern is what happens to the cold temperature performance with the blend.
This may not be much of a concern in most of Cali, but it is for many of us.
YEP when does being a 12 year member on a web site make some one an expert? I look at the content of their posts I spent 40 years of my life fixing engine is a fleet maintenance setting. A major equipment rental corporation. we fixed most anything that came though the doors. Although I haven't been a 12 year member I trust my opinion 100%

 

[kschachn]

So true.

Originally Posted By: CT8
YEP when does being a 12 year member on a web site make some one an expert? I look at the content of their posts I spent 40 years of my life fixing engine is a fleet maintenance setting. A major equipment rental corporation. we fixed most anything that came though the doors. Although I haven't been a 12 year member I trust my opinion 100%

 

[OVERKILL]

Originally Posted By: CT8
Originally Posted By: fdcg27
Originally Posted By: CT8
passenger car motor oils can be mixed by design. You will fortify the weaker oils or dilute the stronger oils. There is not a whole lot of difference between them as far as mixing goes.


So we should ignore what a twelve year member who's an engineer posts and take your word for it?
The real concern is what happens to the cold temperature performance with the blend.
This may not be much of a concern in most of Cali, but it is for many of us.
YEP when does being a 12 year member on a web site make some one an expert? I look at the content of their posts I spent 40 years of my life fixing engine is a fleet maintenance setting. A major equipment rental corporation. we fixed most anything that came though the doors. Although I haven't been a 12 year member I trust my opinion 100%


It isn't that he's a 12 year member that makes me trust him here. It is the facts that:

1. He's an engineer and actually designs bearings
2. He has extensive experience with bearing lubrication in the real world as well as lubricant performance relative to this.
3. He has provided links to actual studies regarding the information he has posted that are from reputable sources like the SAE.

Shannow doesn't "shoot from the hip". When he states something he always has something to back it up. He isn't providing "opinion", he is providing legitimate information.

Also, one needs consider the context of what is being presented and whether it even applies to your situation. The primary potential issue with mixing oils, which Shannow mentioned, is a negative affect on cold temperature performance. Unless your fleet maintenance setting was Edmonton and unaided cold starts were frequent, the odds are you would never be exposed to this potential issue.

It is an issue that likely isn't a reality for any of the states that don't see real winter and also would still require a mix of the particular oils that exhibit the symptom being discussed: A serious reduction in low temperature performance. Which isn't the case with probably many (most?) of the lubricants that DO get mixed in service.

It is a REAL but POTENTIAL issue. It doesn't mean it happens every time. It doesn't mean it happens frequently. But there has been information provided that it is a real issue.

Also keep in mind we are discussing mixing oils together, not using one oil after another in an OCI where the only mixing taking place is with the small amount of residual oil.

 

[CT8]

Good but oils are compatible and the higher quality oil is decreased and the lesser oil is increased. As I posted.Realistically in the real world you can mix oils and millions of mix oils just because or as a blend or add oil. I have dealt with EFU for most of my life, no offense engineers.

 

[OVERKILL]

Originally Posted By: CT8
Good but oils are compatible and the higher quality oil is decreased and the lesser oil is increased. As I posted.Realistically in the real world you can mix oils and millions of mix oils just because or as a blend or add oil. I have dealt with EFU for most of my life, no offense engineers.


It isn't quite that simple though.

Please read this:
http://www.bobistheoilguy.com/forums/ubb...922#Post3503439

It will get you on the same page regarding what is being discussed. Of interest are the comments made by Tom NJ and Molakule, both of whom have participated in or participate in oil formulation.

Note, that as I already said, the potential side effect (reduced CCS/MRV performance) would only be a potential issue for somebody where the temperatures at which they are measured are relevant. Given your location, that isn't you.

 

[Garak]

Originally Posted By: OVERKILL
The primary potential issue with mixing oils, which Shannow mentioned, is a negative affect on cold temperature performance.

Agreed. And the miscibility standard does nothing to guarantee or predict an XXw- value of a mix, or much else, for that matter. I'm sure most mixes would be absolutely fine, but you're not going to see oil companies standing behind, much less providing figures for, mixes of their product with that of a competitor.

Originally Posted By: OVERKILL
Also keep in mind we are discussing mixing oils together, not using one oil after another in an OCI where the only mixing taking place is with the small amount of residual oil.

Additionally, as I've stated before, I'm confident that part of the rationale of the standard would be so that one could top up a low sump with confidence, without having to go through a big production of getting exactly what's in the sump for top up.