Can similar spec'd, but different brand, oils be mixed?
 

I'll be doing my own oil change on the coupe and was wondering if different brand oils can be mixed. Last year Castrol EDGE 0W-40 (MB approved 229.3/229.5) was used. I have approximately 3 quarts left and was wondering if that could be mixed with 4 quarts of Mobil 1 0W-40 (Longlife-01, also approved by MB). It would seem to me that I can as both oils have the same specifications approving them for the C-300 2L turbo.

The short answer to your question is yes, you can mix those two oils. The resulting frankenbrew won't be optimal because the add-packs aren't complementary. Just buy a 5qt jug of Castrol 0w-40 on Amazon for $23 and use that with the 3qts you have left over from last time. That would be best for the engine.
Btw, Mobil 0w-40 no longer carries LL-01 approval, and hasn't for several years. That is a BMW spec that the curent formulation of Castrol still meets.

Our cars need oils listed on sheets MB229.5 or MB229.6
https://bevo.mercedes-benz.com/bevol..._en.html#close

Hey SAT, good to know that there are some few people on this forum that know a little something about these cars. I've already bought another 5 gallon jug of Castrol Edge 0-W40 at Walmart for $25. Walmart is really good for getting 5 gallon jugs of oil for a good price. BTW, in the past for my BMWs I've always used Mobil1 and would have used it for the C300's first oil change, but no one had it and I wound up getting the Castrol Edge as it had the same 229.5/229.6 spec as did the Mobil1.

And as for M1 no longer carrying the LL-01 spec, it could be that M1 still meets it but doesn't want to pay Mobil the licensing fee to have it on the label???