Alternating Oil Brands

[DGXR]

The guy at work who is using this method of alternating, see's it as beneficial.

Warm fuzzies are the only meaningful benefit this guy will get from alternating oil brands. Tribologists will argue the merits of each oil formulation applying a protective layer/film on engine parts. These protective films are more intended to protect the engine in emergency conditions (overheating, lack of oil) which goes beyond the scope of your question.

But still... here is my understanding: different oil formulations apply protective films on engine parts using different additives, or different concentrations of the same additives. Apparently, changing between different oil brands *MAY* result in the removal of the protective film from the previous oil's formulation, followed by the application of a protective film from the current oil's formulation. The period in-between protective film layers *CAN* produce higher wear metal numbers in an oil analysis. But all the wear numbers I've seen in this scenario are very small and not a reason for concern, even for long-term ownership. YMMV

 

[DavidJones]

If it makes him happy, he could use a different brand every time. The vehicle won't care.

 

[Tdbo]

If it meets API rigor, and the specifications of vehicle manufacturer, what does it matter?
Low bid all the way!

 

[MSCH]

Warm fuzzies are the only meaningful benefit this guy will get from alternating oil brands. Tribologists will argue the merits of each oil formulation applying a protective layer/film on engine parts. These protective films are more intended to protect the engine in emergency conditions (overheating, lack of oil) which goes beyond the scope of your question.

But still... here is my understanding: different oil formulations apply protective films on engine parts using different additives, or different concentrations of the same additives. Apparently, changing between different oil brands *MAY* result in the removal of the protective film from the previous oil's formulation, followed by the application of a protective film from the current oil's formulation. The period in-between protective film layers *CAN* produce higher wear metal numbers in an oil analysis. But all the wear numbers I've seen in this scenario are very small and not a reason for concern, even for long-term ownership. YMMV

why would the protective film of one brand be removed until the engine is already running where the anti wear stuff is already doing it's thing.? I'd be more of the opinion it just gets replaced or blended with whatever is in with the replacement oil