additive clash - any experiences ?

[bonnie john]

i'd heard of it, like a lot of internet "truths"

but haven't spoken to anyone who's had it

so what happens, and can the layman detect it?

or is this a lab thing ?

 

[JHZR2]

It could precipitate, yes, but the bigger concern is the competition for surface coverage due to an imbalanced additive pack, resulting in less protection/more wear.

Tough to prove even at a UOA level, just because acquiring consistent tests is touigh, and there are lots of variables, but very easily proven in the lab.

 

[ARCOgraphite]

There was just a very lengthy thread on this.
I've mixed oils, and manytimes the engine ran "rougher" and had less torque with the mix. Rarely, I've mixed oils and the engine ran smoother. MC5K 10w-40 mixes well onto 5w-30 MC5K; but Castrol Syntec 10w-40 didnt mix well into 5w-30 syntec(!) M1R4T (up to 1 qt) mixed well into 10w-30 ashland Synpower.

 

[Kruse]

Originally Posted By: ARCOgraphite
I've mixed oils, and manytimes the engine ran "rougher" and had less torque with the mix. Rarely, I've mixed oils and the engine ran smoother.


Do you think you could pick this out in a blind test? I guess a lot of people just have more perception than me.
I've used lots of different oil in my vehicles and I guess I just don't pick up on the little nuances that results in the mixing, as you say.
Maybe I just need to pay more attention.

 

[eljefino]

I mixed 4 or 5 leftover quarts all brands once. Draining, there was the usual stream but also driplets that were separate from the main. That kind of creeped me out.

 

[PT1]

I have mixed random quarts for years. But usually less than a quart of one brand in a fill of another. No difference.

 

[Steve S]

All the additives are the same throughout all the formulaters and are compatible. Look at the UOAs ot the virgin oil analysis posts.

 

[Eddie]

Inexpensive VOAs & UOAs do not examine all molecular weight additives. They check only the more common known additives.

 

[Steve S]

They are by design made to be compatible.

 

[edhackett]

Compatible and working ideally when mixed are two different things.

Ed