Mixing 5W30 + 5W50

[bwco]

is it safe to mix equal amount of Mobil 1 full syn 5W30 with Mobil 1 full syn 5W50 for a 4.3L V8 low revving engine that ask for thick 30 weight or normal 40 weight.
The engine has approximately 100K miles but not burning oil due to the low revving low end torque engine, it rarely see high rev in it's entire life. Please provide suggestion.

* i know i should get the proper 5W40 oil, but I have 50L of 5W50 left from my Porsche. So, my only choice now is use it up by mixing on my other cheaper cars.

 

[StevieC]

Safe to do.

 

[FrankN4]

Mobil 1 says it is OK to mix..er.. I mean blend them.

 

[Dominik]

I've done it using 50/50 mix or close to it using Syntec and Quaker State, lately M1 15w50 1.5L + 2.5L M1 5W30 in 4 cyl Acord with 180,000km no problems yet, no start up noisse, engine is sluggish any how so cant tell if it makes any difference had used 5W20 in it this spring for 4000km but it semmed to dissappear (about 1L during that interval). With thicker mix no consumption. It was Mobil's site that finally conviced me to do it, since they say it is safe to mix/bled

 

[HTSS_TR]

It's best to mix oils of the same brand, M1 with M1 is perfect.

 

[hate2work]

Originally Posted By: HTSS_TR
It's best to mix oils of the same brand, M1 with M1 is perfect.


I used to think this as well, but I'm drifting the other way these days. I've never seen any evidence to suggest that any harm will come from mixing any brand of oil with any other brand.