pikemike428

So i had my oil changed with Royal Purple Synthetic when I did my headers/x pipe/spark plugs/msd wires/tune about 1500 miles ago, and wanted to top it off. I have 2-3 quarts of Mobil 1 5W 30 in the garage. Would it be sacrilegious to top off Royal Purple with Mobil 1??

Also-have a brand new set of AC Delco OEM ROTORS/PADS/PINS that I will work on this weekend and next as I am sending my calipers off to get powder coated. What is the brand of choice for brake fluid?? Anything else that I should change or look for while doing the change to the new set?? What type of brake fluid is the best? Should i change the brake lines to SS lines while I am there?

Thanks

juanvaldez

It won't hurt anything to mix brands of oil. I like Valvoline Synthetic Dot 4 brake fluid. It is cheap and available at Autozone, etc. Take a look at Speedbleeders, they make brake bleeding an easy one man job.

ticat928

Mobile One 5-30 is oil field sourced (except some of their European Formulas) but undergoes several additional refining stages such as hydocracking thus not a true synthetic under the old marketing rules'

Currently hydotreated oils are allowed to marketed as 100% synthetic but when you look a MSD sheets it is a type 3 oil rather than a type 4 which is a true synthetic base stock oil derived from ester or olifins which is what Royal Purple is (thus the higher price).

I learned above the hard way when I mixed Castrol Syntec with Mobil 1 back in the days Mobil 1 was a type 4 oil made the old fashion way from expensive true synthetic components.

What I did not know at the time was that Castrol was only a hydrotreated Dino oil of type 3 not type 4.
I was not aware of the change in marketing rules of the day.

They did not mix, the make up Castrol oil added to the Mobile 1 (of old) formed globules, I had to dump it all.

I would suggest you do a test mixing outside of the crankcase first.

It is a safe bet type 3 oils can be mixed with other type 3 oils, however I would never mix different brands of type 4 oil, why chance it when one is paying $ 10/qrt and up.