is it OK to mix engine oils?

[sixdogs]

I use sythetic 0W40 in most of my things and because of that don't have a lot of dino oil around. I need an oil change in a newer Kubota that I don't want to switch to synthetic yet and have a gallon of left over Deere 15w40 and could add a gallon of Delvac 15w40 I have in the basement. It saves me from buying more oil. I cant't imagine a problem and wonder what others think?

 

[kensnelling]

Personally, just do it. All oil additives are the same (just some brands use different propations) so it's not like you'll be creating an acid compound in the crankcase.

Ken

 

[LD1]

Last I had heard about oils, is that its okay to mix dino oils as the SAE (or whatever governing body) requires them to be compatible. But that isnt always the case with synthetic oils.

 

[Bird]

Supposedly, 50+ years ago, different brands had different additives or detergents, so I was taught as a teenager to not mix brands. Now I understand that's not the case anymore; they should be compatible. However, old habits are hard to break; I still would not mix brands.:laughing:

 

[kuboman]

John deere explicitly warns against mixing oils. I would not. How many hours on the Kubota. If your past breakin then put in your synthetic.

 

[sixdogs]

John deere explicitly warns against mixing oils. I would not. How many hours on the Kubota. If your past breakin then put in your synthetic.

Not past break in and only 60 hours. Figure 40 more on dino and switch to synthetic.
This dino oil I have is just leftover stuff I'd live to use and get rid of.

 

[PHILIP8N]

How much is your tractor worth? How much is the oil? Will it effect your sleep at night? FWIW, I changed to 5w-40 full synthetic at 50 hours. Philip.

 

[Gary Fowler]

Some manufacturers specifically state a time limit where it is not recommended to use synthetic oils. I would follow that advice however, I wouldnt have any qualms mixing different brands of DINO oil of the same SAE weight specification. They are all compatible in the DINO oil, however Synthetics may not be, so I would stick with the brand that you decide to use and not mix them even when changing oil. Decide what brand you want to use and stay with it as there is a possibilty of some oil being left in the engine when changing. Might not be an issue even with Synthetics but some folks here claim to be knowledgeable of it and say that some synthetics are not compatible with other brands. This might be a myth propagated by the oil companies to keep you using their brand buy why take the chance.

 

[Tig]

I was taught as a teenager to not mix brands.

Cue the steam engine jokes.
FWIW, I was taught to not mix also, so I don't in the machines I like.

 

[LD1]

Cue the steam engine jokes.
FWIW, I was taught to not mix also, so I don't in the machines I like.

What about the machines you dont like?:laughing:

 

[ray66v]

If you check oil manufacturers web sites, they say there is no problem with switching between synthetic and mineral oil. I have never read a FAQ, specifically discussing mixing them, but since you can switch them, you are technically mixing them.

They also state clearly, unless you have an engine that specifically calls for a special break in oil, there is no period of time you need to wait, to switch to synthetic. Many vehicles now come right from the factory with synthetic oil in the crankcase.

The only real difference between synthetic, and mineral oil anymore is, the synthetic oil can handle more extreme temperatures, and provide longer drain intervals.

Lubricity is about the same in both.

 

[Tig]

What about the machines you dont like?:laughing:

They fall to the next level of care. "The oil I have handy is better than no oil at all."

 

[beckmurph]

I use sythetic 0W40 in most of my things and because of that don't have a lot of dino oil around. I need an oil change in a newer Kubota that I don't want to switch to synthetic yet and have a gallon of left over Deere 15w40 and could add a gallon of Delvac 15w40 I have in the basement. It saves me from buying more oil. I cant't imagine a problem and wonder what others think?

If you are worried about using synthetic oil in a new engine, they why would you not be worried about mixing oils?

 

[sixdogs]

If you are worried about using synthetic oil in a new engine, they why would you not be worried about mixing oils?

I don't understand. Deere says not to use synthetic till 100 or 200 hours. I forget which but it doesn't matter. Kubota says zero about synthetic so Deere becomes my proxy for behavior. Personally, I suspect synthetic could be used from the get-go in engines (cylinders) prepped for it but I don't want to guess which ones. And since Deere says to be careful I'm going to be careful.

On the other hand, I don't see a problem mixing dino oils of the same grade yet Deere and Kubota both make reference to not doing it. Yet that defies logic and conventional wisdom and makes a better marketing argument that one based on technical consideration. None of this is brain surgery and personal experience is probably the best answer.

 

[ray66v]

I don't understand. Deere says not to use synthetic till 100 or 200 hours. I forget which but it doesn't matter. Kubota says zero about synthetic so Deere becomes my proxy for behavior. Personally, I suspect synthetic could be used from the get-go in engines (cylinders) prepped for it but I don't want to guess which ones. And since Deere says to be careful I'm going to be careful.

On the other hand, I don't see a problem mixing dino oils of the same grade yet Deere and Kubota both make reference to not doing it. Yet that defies logic and conventional wisdom and makes a better marketing argument that one based on technical consideration. None of this is brain surgery and personal experience is probably the best answer.

I have heard from members that Deere does have some equipment that still requires a break in oil.

It will be a specified type of breaking oil if that is the case.

Breaking a modern engine with ordinary engine oil isn't going to produce a different result than synthetic oil.

All this could stem from the fact that whoever is in charge at Deere, will not accept the fact that it's 2012. Some traditions die hard. Or they have failed to embrace modern manufacturing techniques that others have.

Anyone who knows an engineer knows they are stubborn.

Then again, they may have a good reason for doing things that way. After all it seems to have worked out well for them.

 

[kuboman]

As for mixing oils????Why bother. As for using synthetic there are several car manufacturers that send the car from the factory with synthetic in the engine. Mercedes is one of them. I would not hesitate to switch to synthetic.

 

[Alien]

Never mix synthetic and mineral based oils... You may finish up with a gooey mess

 

[sixdogs]

Never mix synthetic and mineral based oils... You may finish up with a gooey mess

I would never do that but how could that be? Don't API oils have to be compatable?

 

[MHarryE]

Since synthetic blends are common and they combine about 30% synthetic with 70% mineral oil, I don't understand why your doing the same mixing will screw things up.

 

[ray66v]

Since synthetic blends are common and they combine about 30% synthetic with 70% mineral oil, I don't understand why your doing the same mixing will screw things up.

Agreed. It would seem to me there would be warning labels on both types of oil, and the engines, saying not to mix them, since it could easily happen when someone adds oil.