Hypothetical Question - Mixing Oils

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Hypothetical situation. If you were to take five synthetic 5W30 oils, say Mobil 1, Castrol Edge, Pennzoil Ultra, Royal Purple and Motul and you were to take a litre of each, mix them and then use that mix in your car, what would you get? Would it be a really good, well rounded oil or would you be left with something that just didn't work? Let me know what you think!
 
I dont think it would ruin anything,but it sure would create an uneven balance of additives.You might overdose on some severely.
 
You would end up with a truly mediocre oil. Different formulations from each brand, so in effect, you would be diluting anything good in each one. For instance, if one uses calcium detergent and uses 2500 ppm, but another uses magnesium and uses 2500 ppm, your blend would be 1250 of each, and likely too low a concentration of either to do much of anything.
 
Might be a little worse, but just as easily might be a little better.
Why assume worse?
The incredibly precise testing to determine either way is not available.
 
The only benefit of this is if you were broke and you had one of each of these in your possession.

I assume (hope) this ain't the case.
 
I mix and blend oils all the time. However, I usually try to stay within the same family of oils. Just look at my sig....Delvac, full strength 15w-40 might be a little too heavy as a stand alone oil....so I thin it out with some Mobil Super Synthetic 0w-20.

The oil is running just fine and I have the flavor of Synthetic group III with the exceptional cleaning and lubrication of Delvac.

I've not seen 1 documented case of a UOA showing poor or damaging results as a direct result of mixing oils. Anyone who says that you should not....with hysterical paranoia without facts to show you in a UOA.....IMO....is talking out of their hat.

Mix away....is what I say.
 
Ive done 3 different syns. SuperTech, Synpower and Royal Purple all mixed and it ran excellent for a year in my yaris.
 
Originally Posted By: NHGUY
I dont think it would ruin anything,but it sure would create an uneven balance of additives.You might overdose on some severely.


I don't see how you could overdose on anything, let alone severely...the blend will always have less of everything than all of the oils that make it up (except basestock, the blend could have more basestock per litre than some of the components)
 
The safest mix is within brand and type, I mixed Synpower 5W20 with Synpower 5W30 and M1 0W20 with M1 0W40 and may add 1/2 to 1 qt M1 15W50 in the summer.
 
I had a neighbor once who was convinced you had to use the same oil without variation or grave damage would result. Once while doing an oil change on my 01 Camry he came over so just to mess with his head a bit Iput in a quart of Citgo Syngard, a quart of Shell dino, a quart of Supertech, (all 5W30), and to top off the additional .7 of a quart I put in some Rotella 5W40 Syn. He told me dire things would happen. I drove the car with that mix for 5k and it's still running fine 100k later.
 
It might be better than the worst of the lot but would likely be worse than the best. Would it end up worse or better than average? Considering the amount of testing done to properly balance additive packages I suspect it would be worse than average but their is no way to know for sure.

PS Ive found the TBN of Rotella Triple Protection holds up slightly better than Rotella T3 but 80% T3 / 20% RTP (Add oil) tends to show roughly a 10% lower TBN than T3 alone.
 
Originally Posted By: mechtech2
Might be a little worse, but just as easily might be a little better.
Why assume worse?
The incredibly precise testing to determine either way is not available.


You're right.

If cleansing is increased, so much fighting there 'might' cause 'some' spike in wear.

Nothing detrimental, though.
 
Originally Posted By: judsonj
I had a neighbor once who was convinced you had to use the same oil without variation or grave damage would result.


That was pretty common in the 70s and 80s here.

Techs would talk additive clash, and the oil left in the sump on a drain etc. ... dealerships were pretty much Castrol and Valvoline, and slagged each other pretty badly.
 
Right now I'm running Chevron 10W-30 with Chevron 10W-40 mixed 50/50.
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What if you ran Mobil 1 with a pint of pancake syrup?

I think the car would like it, especially if it's a fan of breakfast foods.
 
Originally Posted By: Shannow
Originally Posted By: judsonj
I had a neighbor once who was convinced you had to use the same oil without variation or grave damage would result.


That was pretty common in the 70s and 80s here.

Techs would talk additive clash, and the oil left in the sump on a drain etc. ... dealerships were pretty much Castrol and Valvoline, and slagged each other pretty badly.


That sounds like the same mentality which drives millions of people to get to the last pump with fuel in order to 'have security':

Fear.
 
Those are all good quality oils. Your engine would run well on any of them. I bet a used oil analysis of that mix would come back better than average. Your engine will not know the difference.
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How would the viscosity behave in mixing say, 9cSt and 13cSt oils in 1:1? I'm thinking M1 0w20/0w40.
 
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