Mixing different oil brands and weight?

[OceanRuns]

Would there be any negatives effects from mixing say two bottles of Pennzoil 10w-40 with two bottles of Castrol 5w-30? All dino oil.

 

[Oregoonian]

Should not make a difference in my mind. When mixing...it might be slightly better to mix oils of the same brand.

You'll end up with a 7.5 X 35...or something close.

 

[ctrcbob]

At the moment, in one of my cars, I have the following:

2 quarts Castrol Edge 5W-30
2 quarts Mobil-1 5W-20 EP
2 quarts Mobil-1 0W-20 (Eco - Green lable)

This is working out GREAT, and I love it.

Next change, I will do the same except I will use
2 quarts Mobil-1 5W-30 EP vice the Castrol Edge.
The other 2 + 2 will stay the same.

 

[Ben99GT]

A random blend likely won't be as optimized as a single oil but most readily available oils are fully compatible with each other.

 

[fdcg27]

I doubt there'd be any negative effects, but there won't be any positive ones either.
If you just need to use up the oil, and don't plan a long run, it certainly won't do any harm.
I used to do this kind of thing all the time, before I at least thought I knew better and I never saw any ill effects.

 

[hpichris]

as long as you don't plan on running it in extreme weather conditions, I don't see any issues.

 

[CATERHAM]

Originally Posted By: Oregoonian

You'll end up with a 7.5 X 35...or something close.

There's no such thing as a 7.5-35 grade.
What you'll likely end up with is either a heavy 10W-30 or light 10W-40.

If you want to know the viscosity outcome of any blend you need the KV40, KV100 and HTHSV of each oil and insert into a viscosity calulator as was discussed in the following thread:

http://www.bobistheoilguy.com/forums/ubb...113#Post2423113

 

[bobfather99]

Mix away.

 

[Scum_Frog]

I'd like to see a UOA on such a Frankinstien LOL

As they are all good oils, the result will probably be just as good.