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Mixing oil brands?

H

Hoss in IL

NAXJA Forum User
Location
Illinois
I have a bunch of mix-matched quarts of oil left over from oil changes from different vehicles. Is it not a good idea to mix different brands of oil if the weight (viscosity) are the same? Just to be clear, I'm not mixing conventional oil and synthetic, just BRANDS.
Thanks, Hoss
 
Hoss in IL said:
I have a bunch of mix-matched quarts of oil left over from oil changes from different vehicles. Is it not a good idea to mix different brands of oil if the weight (viscosity) are the same? Just to be clear, I'm not mixing conventional oil and synthetic, just BRANDS.
Thanks, Hoss
Click to expand...

I do not think it will do any harm, But It is not recommended.
I personally would save the mixed batch oil to use as part of a clean & flush for When the engine is very dirty & ready for a clean out!
 
i have never had a problem, that i can tell, with mixing oil brands on my 89 with 232k miles.

who says its not recommneded? on every bottle ive seen, it says the oil is compatable and can be mixed with other engine oils.
 
89xj said:
i have never had a problem, that i can tell, with mixing oil brands on my 89 with 232k miles.

who says its not recommneded? on every bottle ive seen, it says the oil is compatable and can be mixed with other engine oils.
Click to expand...

Right out of some old SAE Hadbook I have
Mixing brands is not the best practice because the additive systems in each may be different and when mixed may not function as efficiently as desired. However, no serious problems will occur if you must add a different brand of equivalent quality between oil changes. It is very important to maintain proper oil level.
Like I said you can do it & not cause any harm, adding a quart of different brand oil will not do anything, But adding 6 different brands is really pushing the envelope.
Why take the chance & risk a $2K+ engine for $20 worth of oil?

Edited to add: I did a quick google search & came up with the exact same statement in an oil myths page from Citgo!
http://www.citgo.com/ConsumerProducts/Oils/EngineOilMyths.jsp
 
Here is the actual law regarding Oil viscocities...

ALL manufacturers of oil must use the SAME scale for determining oil viscocity. This also means you may mix different oil manufacturers oil of the SAME wieghts.

However it is not recommended to mix different WEIGHTS...

In short:
Same weights, different brands=OK
Same brands, different weights=NOT OK

This law insures that oil A 10w30 can be mixed with oil B 10w30 and not do any harm.

Also, if you are really picky, you can mix synthetics with naturals of the same weight. How do you think they get synthetic blends??

Sorry, working in a parts store, I had to explain that one quite a few times....
 
Poorboy, that's kind of what I was getting at-same weights, different brands-maybe I didn't ask it the way I was thinking it.
Thanks for the input.
Take care, Hoss
 
poorboy_616 said:
Here is the actual law regarding Oil viscocities...

ALL manufacturers of oil must use the SAME scale for determining oil viscocity. This also means you may mix different oil manufacturers oil of the SAME wieghts.

However it is not recommended to mix different WEIGHTS...

In short:
Same weights, different brands=OK
Same brands, different weights=NOT OK

This law insures that oil A 10w30 can be mixed with oil B 10w30 and not do any harm.

Also, if you are really picky, you can mix synthetics with naturals of the same weight. How do you think they get synthetic blends??

Sorry, working in a parts store, I had to explain that one quite a few times....
Click to expand...

I've mixed different weights on quite a few occasions, same brand though, I've done 5 quarts of Mobil-1 10W30 and 1 quart of 5W30, I've also mixed 10W30 with 20W50. The 5W30/10W30 is how I used up the 5W from the wifes oldsmobile, I had a couple of cases and 5 quart jugs of that when we got rid of the olds. All Mobil-1 though.
 
right now im running 4qts rotella syn 5-40 and 2 qts rotella dino 15-40.

i dont see a problem and dont see the problem of mixing brands.
 
I used to make a slightly heavier 10w40 in my Mazda by using 3 quarts of 10w40 and one of 20-50. That shut the rods up nicely....

I just wouldn't recommend doing at the time of sale....
 
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