Mixing different types of Synthetic Oil...
Thread Starter
Senior Member
Joined: Nov 2011
Posts: 308
Likes: 22
From: Houston TX
2015 E400
Mixing different types of Synthetic Oil...
Between our various BMW, Mercedes, Corvettes, Audi & Jaguar vehicles in our family, we all use Mobil 1, Castrol, & Pennzoil synthetic oil 5 quart jugs of various viscosity of 0w20 to 5w30.
Since we don't always use the full 10 quarts of the 2 Five quarts, there's always a few quarts left over this 5 quart jugs.
So question is: Is it OK to mix between:
- different brands of synthetic oil (Mobil 1 + Castrol, etc...)
- different viscosity (0w20 + 5w20, or 5w20 + 5w30, etc...)
- different shelf life/age (been sittin' on garage shelf for 1 yr + 2+ yrs...)
Thoughts...?
Thanks,
Since we don't always use the full 10 quarts of the 2 Five quarts, there's always a few quarts left over this 5 quart jugs.
So question is: Is it OK to mix between:
- different brands of synthetic oil (Mobil 1 + Castrol, etc...)
- different viscosity (0w20 + 5w20, or 5w20 + 5w30, etc...)
- different shelf life/age (been sittin' on garage shelf for 1 yr + 2+ yrs...)
Thoughts...?
Thanks,
Member
Joined: Aug 2017
Posts: 85
Likes: 16
From: LA
E350
I'm not a expert but I think you should ask here: https://www.bobistheoilguy.com/forums/ubbthreads.php
Here are my opinion on your questions
- different brands of synthetic oil (Mobil 1 + Castrol, etc...) It's fine as long as they meet the spec of your car that your trying to fill.
- different viscosity (0w20 + 5w20, or 5w20 + 5w30, etc...) This will change the viscosity of the oil depend upon the mixture. ie. 5 quarts of 0w20 + 4 quarts of 5w20 will get you something between the 2 mixture viscosity....2w20?
As long as it's close enough to what's recommend by manufacture, your fine.
- different shelf life/age (been sittin' on garage shelf for 1 yr + 2+ yrs...) For sure not the 2+ years left over oil as once you open the seal, it get oxidized. It degrade the quality of oil(chemical break down) and increase viscosity. 1+ years, probably not. 0-0.5 years opened, you could use it imho.
You can use oil as long as it sealed and hasn't past the expiration date and store in a cool dry location without any water or dirt that has gotten into the bottles.
Here are my opinion on your questions
- different brands of synthetic oil (Mobil 1 + Castrol, etc...) It's fine as long as they meet the spec of your car that your trying to fill.
- different viscosity (0w20 + 5w20, or 5w20 + 5w30, etc...) This will change the viscosity of the oil depend upon the mixture. ie. 5 quarts of 0w20 + 4 quarts of 5w20 will get you something between the 2 mixture viscosity....2w20?
As long as it's close enough to what's recommend by manufacture, your fine.- different shelf life/age (been sittin' on garage shelf for 1 yr + 2+ yrs...) For sure not the 2+ years left over oil as once you open the seal, it get oxidized. It degrade the quality of oil(chemical break down) and increase viscosity. 1+ years, probably not. 0-0.5 years opened, you could use it imho.
You can use oil as long as it sealed and hasn't past the expiration date and store in a cool dry location without any water or dirt that has gotten into the bottles.
Senior Member
Joined: Aug 2014
Posts: 255
Likes: 36
From: Las Vegas
2012 E350 sedan
Agree that you should check the Bob site and please let us know. Also agree that if you mix viscosities of the same brand & spec, the result will be somewhere in between. I've always added Mobile 1 to my cars between oil changes, with a total add between changes usually being less than 1/2 qt. My MB dealer uses Mobile 1 but my Audi dealer uses Penzoil synthetic. I've never had a problem. Also not being an expert, I'm immediately leery of mixing brands on a large scale as the OP suggests. Oil naturally is a single viscosity. Multi-viscosity (like 0-30) is achieved by additives to the oil. Large scale blending of oil from multiple manufacturers could have the combined additives working in an unexpected way, perhaps even hindering each other, so the spec of the blended oil would be unknown.
