I havn't been able to find a whole lot of information on 0w20 and 0w30. Seems like people stick to either 20wt or 30wt per their manual and anything in regards to 20wt vs 30wt is a can of worms with the two sides fighting. I dont want this thread to turn into a [censored] show. Per my manual 0w20 is recommended, but I can use 30wt as well. I've been using 5w30, but with recent cold temperatures in the single digit Fahrenheit I get a lot of knocking/tapping sounds from the engine during cold start up for a good minute or two. As far as these kinds of cold temperatures go will 0w20 flow/pump better or 0w30. I know both oils have a 0w rating but I am comparing apples to oranges. If it helps the 0w30 oil will be Mobil 1 since it seems to be the only one with the ILSAC GF-5 rating, and the 0w20 would be a Toyota Genuine oil. I'm not trying to get into a whole debate about 20 vs 30 oil or why I'm using 30 weight oil. So if we could stick to facts I'd appreciate it.