[bobkat09]

I'm switching oil brands from Mobil 1 0w40 to Castro Edge 0w40 and have a couple of quarts of M1 left. Is it ok to use 6 quarts of the Castro and 1 quart of M1 together? They are the same viscosity.

[bavarianride]

Maybe just keep the M1 as top-off oil?

[Kolyan2k]

You can mix viscosity as well, nothing gonna happen to engine obviously. And with 1 quart left it can be an olive oil....

[John 070]

I say no worries...if me, I would just want it to be LL-01....others don't care, probably doesn't even matter....

[StevenY.]

Same situation as you except I have 4 quarts of M1 from last year. Guess I will mix with castrol 0w40?

[BeastMode335i]

Don't do it, your car's going to self implode..!!

j/k you'll be fine..

[Needbmwpartzz]

It's ok.....just don't add if the oil has sand in it.

[Kolyan2k]

Ps. My dad added 1qt of tranny fluid to engine..... Still nothing happened....not that I was worried or anything.

[barefootin]

Originally Posted by Kolyan2k

Ps. My dad added 1qt of tranny fluid to engine..... Still nothing happened....not that I was worried or anything.

This my friend is what we call a back yard Hill Billy Mechanic fix for cleaning coaking, gook, and gunk from internal engine components. Works surprisingly well to quiet sticking lifters also.... The down side is the plugged pick up screen/tube, oil starvation, and bearing damage. Especially if the engine was a victim of poor PM or design flaws in the PCV system.


I tore apart a Audi engine that suffered this ill fate many years ago... I never saw such pretty colours in metal! The crank and rods were scored beyond description and to the inside of the journals the crank was literally iridescent shades of blues, reds, and purple.... Needless to say, I never went past pan removal after seeing that before informing the gent he had nothing but a 5cyl paper weight.

To the original OP... Mix away....

[hassmaschine]

Originally Posted by Kolyan2k

Ps. My dad added 1qt of tranny fluid to engine..... Still nothing happened....not that I was worried or anything.

tranny fluid is just oil with a lot of detergents & additives. I mean, don't fill your whole engine with it, but it's common to run a quart through an old gummed up engine to clean it out a bit.

[twinboost_MD]

your good