Mixing Oils in a 1997 Landcruiser

[Shannow]

Originally Posted By: Dallas69
I've been here awhile now and in a past life longer and never once saw any posts on problems.


Originally Posted By: Shannow

https://bobistheoilguy.com/forums/ubbthreads.php/topics/4257160/Re:_New_Mobil_1_Racing_0W30_VO#Post4257160

May or may not have blown chinks, depending on how careful the poster was with mixing.


from this thread, and
https://bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2948797

which is another link that I've given you where a mixer ended up with viscosity results that differed from the expectation provided by the widman mixing calculator...

like I said, in order for mixing to be scientific, the interaction of the additives and basestocks has to be linear, and additive...they aren't.

 

[650NutKase]

Good point. In my mind, I just really don't see any issue with running maybe one qt Castrol, the rest Rotella. In the end it's his decision and we are just giving input. He already has gone away from what is "Ideal" by running a cj-4 oil instead of the recommended 5w30 for the 4.5l engine, so in the end, who is really right?

 

[Shannow]

Only time I will ever tell a poster not to is if they live in a 0W climate, and need the 0W.

Otherwise, as Crowley stated, "do as thou shalt"


Somehow, countering the "never been a problem" guys gets translated into "do it and your car will die along with the other pile of failed engines at the side of the road"...as can be clearly seen in this thread.

 

[650NutKase]

Well said, sir

 

[Garak]

Originally Posted By: Dallas69
I don't know of anyone who has had any oil related engine problems with mixing brands of oil.

I don't know anyone personally who intentionally mixes oils, and I've been around cars all my life, but that doesn't mean it doesn't happen, either. Documentation has been posted, and that's better than "first hand knowledge," because there are probably fewer than ten people on this board who actually would have the credentials to make such a diagnosis in the first place.

Originally Posted By: 2012AccentSE
He already has gone away from what is "Ideal" by running a cj-4 oil instead of the recommended 5w30 for the 4.5l engine, so in the end, who is really right?

Going out of spec in name only is not the same thing as mixing. Given what the vehicle likely calls for in other parts of the world, perhaps it wouldn't be out of spec at all.

And, I've stated before, that there are reasons to mix. One can fine tune viscosity. It's particularly useful with certain racing oils. That doesn't validate the procedure for other scenarios. The pitfalls have already been addressed. That doesn't mean you positively will encounter them. You almost certainly won't.

With respect to mixing happening when changing oil anyway, well, what if one buys a substantial quantity all of the same lot number and uses that for several consecutive oil changes?

 

[tom in boise]

I appreciate all the comment and debate - very interesting. These things (4.5l Landcruiser engines) are basically a legacy design forklift engine built for 3rd world countries where the next oil fill will be whatever is available. The original 5w30 oil specified with North America only, in an attempt to improve fuel mileage (laughable, really, considering the vehicle platform).

Anyway, I believe for this next fill I will use my 3 qts of Castrol 20W-50 and 5 qts of Castrol 0W-40 and see how it goes (watching consumption). Most of my leaks have been taken care of.

After that I will likely move to a Mobil 1 5W-40 or 10W-40 of some type.

 

[Garak]

I would expect, too, it can handle a wide range of viscosity. A 5w-40 would be just fine year round, assuming the leaks don't get you, but you say they're mostly addressed.