Mixing oil viscosity

[fiddle mike]

I've accumulated some partial quarts of oil over the years and am wondering about mixing them.  I've done a search on the Tech board as well as Calci's "All About Oil" and some motorhead forums but can't find the question I want to ask.

I want to know if anyone has mixed different viscosity of different brands.

 Ferinstance:  I have partials of Rotella T 5w40, Mobile1 15w50, and Honda GN4 10w40. 

[CajunRider]

I've done it once or twice... usually when topping off the oil level on a burner (KLR650, XR100, etc..). 

I never saw any "damage"... but then again, I wasn't really looking and it was only done a few times when I didn't have the oil I normally use. 

[3fan4life]

I found this with an internet search:

Can you mix motor oil viscosities?

In:Oil and Oil Filters [Edit categories]

Answer:
 
Short Answer is Yes but don't mix brands


Long answers

From the Chevron.com site:

"Can I mix different viscosity grades of motor oils?"
"Yes. It is always advisable to not mix motor oil brands, however, different viscosity grades of the same brand motor oil are compatible. Be aware that mixing viscosity grades will turn out a product that is different in viscosity than either what was originally in the engine or what was added."


From Shell.ca:

"If you mix viscosity grades such as a 5W30 low-viscosity oil and a 10W40 higher-viscosity oil, it is reasonable to expect that the resulting product will have viscosity characteristics which are thicker than the 5W30, but thinner than the 10W40. This change does not reflect incompatibility - it's simply a re-balancing of the viscosity characteristics. In all other ways, the product should work as expected. But there's absolutely no danger about incompatibility resulting from mixing engine oils," Miller says. "We've tested all of our grades and brands, and we haven't observed any problems."



From Mobil1.com:

"For our customers to choose a viscosity grade, we recommend they follow the engine manufacturer's recommendations as indicated in their owner's manual. There is no need to mix two Mobil 1 viscosity grades when one will do; however, we see no problem mixing different SAE grades of Mobil 1 Tri-Synthetic series motor oils."


Read more: http://wiki.answers.com/Q/Can_you_mix_motor_oil_viscosities#ixzz23r5U7Rge

Oil is one of the few things that I am very picky about and will not cut corners on.

I wouldn't mix viscosities or brands if I didn't absolutely have to, But it would appear that it is OK.

[Tropic traveler]

Jeez, I've mixed oils plenty of times to top off some of the oil burners I've owned in days gone by. 

[fiddle mike]

I found this with an internet search:

I saw a couple of those.  Advice on mixing brands was part of what I was looking for.  Calci dismisses a lot of the "secret ingredients" as snake oil so I thought I'd try to seek out some real world advise.  I just hate for those partials to go to waste.  I may use them in my mini truck.

[Thunderbolt]

the one that you squirt those rusty bolts and nuts with to get them loose.

[Michvalk]

I use any extra oil in my lawnmowers, rototiller, stuff like that.

[Ricky-D]

Most all oil is the same.

The difference comes with the additive package that the brands contain.

Some additive packages can react with other brands additive package.

This should be enough reason to not mix different brands of oil.

I have no hesitation mixing oils that are the same brand. Weight notwithstanding!

***

[R J]

In the shop we have a tray we can put empty bottles of oil in so it can drain on out.

If the lawn mower, it is a 2 stroke, and yes, it will run on this junk oil, or our squirt can gets low we use this to fill it up.   I think we have about 6 of these squirts cans in the shop.

We put the little barrels of this reclaimed oil in the storage shed till winter.    Then it becomes the oil for our old oil burner furnace.     Works super good and is about as cheap, $$$ wise, as we can get.   And it is a dirty bitch to clean no matter what you use for oil.