Now that a lot of synthetic oils are apparently Group III can a person mix these oils without problems? Now, I don't normally mix oils of different brands anyway. But if I switch from one Group III oil to another will that cause any problems? Otherwise if I am low on oil I will add conventional motor oil even if it is not the same brand of oil. For example, if I am using Pennzoil Platinum synthetic oil and I am somewhat low I will add conventional motor oil to bring it to the correct level. It seems you should be able to mix conventional oil with Group III synthetic. But if I switch from one Group III to another will the Group III left in the engine cause any problems?
Mixing of Group III oils
- Thread starter Mystic
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It all says it is compatible so I would not sweat it. Not make a habit of it but not sweat it either.
It should be absolutely fine.
So buy an extra quart or two of PP or a Penzoil dino oil and put them in your trunk for those times. Then you don't have to worry about it. That also would help your 6-P's.
Not a problem...I mix whiskey, beer & wine all the time..
So if we mix two GP3 oils at a ratio of 50/50 we will get only 50% of the add-pack for each. May be OK for you but, not to me. Oil producers formulate their add-packs with a specific ratio of ingreadents to offer the most engine protection for that oil. Why would I want to dilute the add pack?
Eddie, I have no intention of mixxing 2 Group III oils 50/50. But I might switch from one brand to another and when you change oil there is some oil left in the engine.
For an add oil I see no reason to use expensive synthetic oil. Conventional oil can be used as an add oil.
For an add oil I see no reason to use expensive synthetic oil. Conventional oil can be used as an add oil.
I went the other way.. added a little synthetic to top off. Is that a big no no?
where is the edit button?
what I meant was added a little synthetic to top of the dino..
what I meant was added a little synthetic to top of the dino..
I'm scratchin my head on this one? If you mix 2 qts of fully formulated oil, with 2 quarts of fully formulated oil, you get 4 quarts of fully formulated oil? regardless of the group number. Can't see any problem with it unless there was some sort of additive clash.
From oil change to oil change I can’t see any residual oil left over from the previous change making any difference one way or another.
And as far as mixing different oils … mix away.
My current fill is … (liters) …
0.3 … Castrol Syntec 5w-50 SH … (old bottle hanging around …
…PAO ..!!!)
2 … Motomaster Formula 1 5w30 SM
1.5 … Motomaster Formula 1 synthetic blend 5w30 SJ … (old Esso branded MM, probably a GII/PAO blend)
0.5 … Presidents Choice (Esso) 5w30 SM
And the makeup oil this summer will a MM synthetic blend 5w30 SJ (Shell branded GII/III).
And as far as mixing different oils … mix away.
My current fill is … (liters) …
0.3 … Castrol Syntec 5w-50 SH … (old bottle hanging around …
2 … Motomaster Formula 1 5w30 SM
1.5 … Motomaster Formula 1 synthetic blend 5w30 SJ … (old Esso branded MM, probably a GII/PAO blend)
0.5 … Presidents Choice (Esso) 5w30 SM
And the makeup oil this summer will a MM synthetic blend 5w30 SJ (Shell branded GII/III).
My father mixed 4 qts of Exxon Superflo with a qt of M1 for 78K on his 2000 Toyota Avalon, I bought it, did the same until 100K. From 100K to 125K it has run all M1. This car has been in the shop once for a fuel filter I believe at 85K. I dunno, wouldn't worry about it. He's been mixing for years, never any problems.
Group III Interchange Rules on the Horizon BITOG thread for additional information.
well at least the ones that haven't blown up already from using Fram filters.........
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Not a problem...I mix whiskey, beer & wine all the time..
I'd only have a problem if you were mixing
them in the same glass!
Quote:
Quote:
Not a problem...I mix whiskey, beer & wine all the time..
I'd only have a problem if you were mixing
them in the same glass!
I mix beer and vodka in a glass all the time. The B&V was born!!
On my last oil change on our '02 Tahoe it was 1qt BMW HiPo synthetic 5w30, 1qt 5w50 Syntec, 1qt Syntec 5w30, 1qt Syntec 5w20 and 1qt GC.
All this went to 8,500 miles on the OLM with no problems whatsoever. Well, so much for mixing oils....
All this went to 8,500 miles on the OLM with no problems whatsoever. Well, so much for mixing oils....
Eddie's assumption is if you add 50% of an oil with one addpack to 50% of an oil with amother you have each add pack dilluted to 1/2 strength. However since the add packs are more similar in function and often in chemistry the reality is you have an add pack that 95% strength with the resulting mix. And I have just a much scientific support for this as Eddie has for his 1/2 strength argument but I believe mine % is closer than Eddie's to what would be in my crankcase.
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