Mixing Synthetics?

Status
Not open for further replies.

CCI

Joined
Jul 15, 2009
Messages
371
Location
New Mexico USA
I remember reading here that there are different kinds of synthetic oils -- different base chemistry?

Is it OK to mix synthetics? Like for example 20w-50 Lucas motorcycle synthetic with 20w-50 Mobil 1 motorcycle synthetic?
 
It's okay to mix but it isn't the most optimal for your engine. Just use one of 2 brands, unless you don't have enough for an oil change and don't like to go to store to buy additional quart(s).
 
You can also mix synthetics with non and/or blends.
Some claim that mixing might cause a conflict in add packs, or the new blend might not be 'optimal'.
I have no problem mixing pennzoil with QS products, but I would not mix those with Valvoline because of sodium content difference.
But I would mix Valvoline with Royal Purple.
Could I be making some terrible mistake, unlikely, my engine, my oil, my choice.
Just because you mix 2 different oils does not mean your engine will explode, but BITOG police might try to confiscate your car, so its smart to use anonymous posts, just don't give out your address.
GreenFocus
 
cci,

consider this:

you have a fill of M1 in your motor or tranny or diff.

dump it

then fill with Pennz Platinum.

tell me you got every single drop of M1 out before the PP went in.
what no you didnt? yes, you just mixed.
everybody mixes some on a change.
 
Quote:
API-certified oils must be mixable. It's a core requirement


What MOTORCYCLE oil are API-certified?

I would not mix motorcycle oils, like 2 quarts of XXX with 2 qts of YYY in the engine..
 
Originally Posted By: sunruh
cci,

consider this:

you have a fill of M1 in your motor or tranny or diff.

dump it

then fill with Pennz Platinum.

tell me you got every single drop of M1 out before the PP went in.
what no you didnt? yes, you just mixed.
everybody mixes some on a change.


Quite right.

There is usually about a cup full of residual oil left on the insides of the engine/transmission assembly, even after an extended period of draining when changing your oil is hot.
On some engine designs, there can also be another 100 ml of oil trapped inside the oil scavenging pump, if a conscious effort isn't made to evacuate it when doing the oil change.
Also on other engine designs, < 80 ml of oil is trapped at the oil pickup zone unless the cover is removed to check/clean the filter screen at the time of the scheduled service.


To the OP.
As mentioned above.
All oils that are API certified are required to be miscible with other oils that are also API certified.
So there is always that level of compatibility between them, to facilitate a top off as required anywhere one may find themselves.


If one is concerned specifically about issues regarding additive pack compatibility.

In small ways, the mixing of two different oil formulations/brands or types may not be the gold standard.
But it is almost inconceivable that any "real world issues" will ever be encountered with regard to mixing motor oil. Neither have I ever heard of incidences of issues.

In summary, it's not a problem.

As an aside.
I have had the occasion to observe through Used Oil Analysis, where one particular additive in one oil formulation which was previously used, actually took 2 oil changes over a period of 12,000 kms to be completely washed out of the machine, and to finally end up at the base line levels of the new brand of oil.
 
Last edited:
Originally Posted By: HTSS_TR
It's okay to mix but it isn't the most optimal for your engine. Just use one of 2 brands, unless you don't have enough for an oil change and don't like to go to store to buy additional quart(s).


I've wondered about how it degrades performance. For example, if I mix Pennz Plat with PYB, maybe they did something chemically in there so I'd now get excessive foaming, we simply don't know.

CATERHAM mixes, yet he usually mixes TGMO with Mobil1 products, and he must have consulted with chemists/tribologists at XOM to be sure it won't reduce wear performance.
 
Quote:
I think you will find that Amsoil motorcycle oil is API certified.


No they are not...there is no API Starburst symbol on the containers..
 
Bike oils usually claim they meet a certain API spec. I am sure they likely do...or else I bet someone would have likely taken some company to court given our litigious society that sues when coffee is hot.

But yes...they have not paid to run the oil through the API certification tests.
 
Quote:
I remember reading here that there are different kinds of synthetic oils -- different base chemistry?

Is it OK to mix synthetics? Like for example 20w-50 Lucas motorcycle synthetic with 20w-50 Mobil 1 motorcycle synthetic?


This was the original question and somehow people brought in the API certification thing and so it's okay to mix different motorcycle brands...


I disagree...UNLESS you are conducting UOA's on that mixture the OP suggested you will NEVER know what is happening inside your engine!

I willing to wager NO manufacturer will state in writing it's okay to mix their oil with another brand.
 
Last edited:
Originally Posted By: rossn2
Quote:
I think you will find that Amsoil motorcycle oil is API certified.


No they are not...there is no API Starburst symbol on the containers..



That API Starburst symbol must be an exclusive American thing.
I can never recall seeing it on any motor oil sold here in OZ in my life.

All the labels ever seem to state, is that the oil meets 1 or more of the API specs for petrol and diesel.
The Amsoil labelling on my bottles is consistent with this type of wording as well.

Perhaps it's safe to say that all the oil sold here in OZ regardless of it's intended use, is not API approved because there's no API Starburst symbol on the containers.
 
Last edited:
Originally Posted By: rossn2
Quote:
I remember reading here that there are different kinds of synthetic oils -- different base chemistry?

Is it OK to mix synthetics? Like for example 20w-50 Lucas motorcycle synthetic with 20w-50 Mobil 1 motorcycle synthetic?


This was the original question and somehow people brought in the API certification thing and so it's okay to mix different motorcycle brands...


I disagree...UNLESS you are conducting UOA's on that mixture the OP suggested you will NEVER know what is happening inside your engine!

I willing to wager NO manufacturer will state in writing it's okay to mix their oil with another brand.


Amsoil states on their website for all their motor oils, that it's ok to mix it with other oils in the Compatibility heading of their product description of their motor oil.
However, they do state something to the effect that the performance will be reduced if you mix it with other oils.
Especially the long drain capability.

But they do say that it's ok regardless.
 
Last edited:
Originally Posted By: Robenstein
If they were worried about mixing oils causing damage, they would have printed disclaimers on the bottle.


Quite right.

It certainly wont cause damage.
Oils haven't got to the point where it's the same as the potential risks one takes with mixing coolants.

Especially when compared to the scenario of actually running too low of oil because of an inability to mix them.

I do wonder, if it's possible that the API requirements are hindering the development of better motor oils simply due to the necessity of being miscible with one another for obvious reasons.
 
Last edited:
Originally Posted By: CCI
I remember reading here that there are different kinds of synthetic oils -- different base chemistry?

Is it OK to mix synthetics? Like for example 20w-50 Lucas motorcycle synthetic with 20w-50 Mobil 1 motorcycle synthetic?


Chemically speaking engine Oil will mix with engine Oil... its the mixing of the size of
molecules that determine whether you notice a slight performance drop or not...

In a traditional Mineral (Dino) oil, the molecules varies in size and
composition which gives rise to increase friction and consume more HP.
MineralOil1_zpsb84d032c.jpg


In a fully synthetic oil, the molecules have the same size and
composition which decreases friction and consumes less HP.
SyntheticOil1_zpse53af542.jpg
 
Last edited:
Status
Not open for further replies.
Back
Top