It's time for an oil change on my truck and I just got some Donaldson filters for it so I'm good on filtration at least until I get a bypass setup but that won't be for a while down the road. I have a gallon of Rotella and two gallons of Delo from various places just sitting around.
Here's the question: should I use those and mix them, or get new oil? All the containers are unopened. I'd like to go to Valvoline Blue but I hate to just waste three gallons of oil or let it sit around for some undetermined amount of time until I find a use for it. What do you folks think?

 

As long as they are the same viscosity and grade I say go ahead and use what you have.

 

They are pretty much the same oil I would say you will be fine mixing. It's dino and synth that you don't want to mix.

 

Different oil companies usually use a different additive package.Probably wouldn't hurt to run it

 

Why most synthetics are totally compatiable with dino...

 

Because they are made from different base groups, and will not typically mix.

 

Why? You see synthetic blends on the time.

 

I'd use them. No sense in wasting good oil.

 

If our trucks come with dino oil and if what your saying is true we can not ever go to synthetic. Because you can't get all the oil out.

 

In small amounts like what your referring to, it will not matter. It is the synth that has a barrier that the dyno can not penetrate. That is one of the reasons it is not the best idea to go back to dino after running a full synth. The blends (semi-syth) are built from the same base groups, which allows them to mix. Plus they are not full synthetics any how.

 

If it was me, I'd just buy another gallon of Delo to go with the Delo you have, then next service, I'd get another 2 gallons of Rotella to go with the Rotella you have. But that's just me- I like everything to match.

 

What barrier is that? Ok you talking full synthetics..so group four I am guessing. Like amsoil...this is right off their site:

MIXING AMSOIL
AMSOIL AME is compatible with conventional and synthetic motor oils. Mixing AMSOIL motor oils with other oils, however, will shorten the oil life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

 

also don't mix chevron diesel fuel with sinclair

 

Yes group IV typically should not be mixed with any other group oils. You want to try to mix same weights and groups if you must mix. It is better to not mix any, but mixing the full syth with non syth should not be done.

 

The golden question...why? Maybe when synthetics first came out it was a no-no but a manufacturer said you can mix them...that works for me.