Mixing Oils

[TYVOLS]

Due to the various sales that go on at any given time I have several quarts or half quarts of different brands that are all the same weight. What do you think about mixing them one oil change just to get rid of them?

 

[ryan2022]

Should be fine for a regular oil change interval. I wouldnt make a habit of it, but im sure it wont hurt anything.

Id at least try to stick with the same weight, or if you have to mix weights, stick with a brand or two.

 

[sw99]

I do it all the time and have been doing it for several years. No problems to date and my engines are very clean. My latest creation was QS 5w20, MC 5w20, Havoline 20w50 and a few ounces of MMO...

 

[demarpaint]

I've been doing it in my beater for a while, so far no problems that I can tell.

 

[CompSyn]

If I had to, I'd feel okay about mixing oils produced by one given company, e.g., SOPUS, Ashland, Mobil, etc.

This due to competing additive packages.

 

[pbm]

I used to have no problem mixing oils but since coming to BITOG I've become more aware of additive packages, base oil etc...It would be nice to have a list of which oil uses which (brand of) additive package etc....so that I would know which oils would likely mix better. For instance, I have 3 quarts of the old SOPUS Wolf's Head oil left over and I'm assuming that another SOPUS product (PYB or QS) would be the best to mix for a 4.5 qt. oil change. In reality it might be another brand altogether which has the same additive package.

 

[GMorg]

It is a misconception to think that manufacturers use the same add pack in all of their grades. It is also a misconception to think that manufacturers keep the same add pack through time for a single grade. I think that if you are concerned about making a bad brew, then stay away from mixing oils that have very different base oils. Particularly, ester based oils and group I oils require a different add pack strategy than Group III and PAO oils.

Mix away and feel safe as long as you don't push the oil too long.