Mobil 1 which is what I use in my Miata and most of the time in the Protege does not market a 5w-20 but instead sells a 0w-20. That is what I will be using in the 3 as soon as it is time to change for the first time.
If you do a web search on motor oil viscosity, you will find out that 0w-20 is a direct replacement for vehical recommending 5w-20. A good site to check out is www.amsoil.com If you read Mobil1 0w-20, the bottle itself states it is a direct replacement for 5w-20. I did alot of homework on this. If you would like to use regular 5w-20 oil, it's available anywhere. If you want to switch to synthetic 5w-20, the only brands that make it are Amsoil (www.amsoil.com) and Royal Purple (www.royalpurple.com). Myself, I am going with the Mobile1 0w-20 synthetic since Mobil1 synthetic is all I have used and all I will use.
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