I'm starting to use honda genuine 5w 20 in my 2.3L Thing is oil change at sears costs me 16 bucks with a honda filter as long as I use valvoline brand, makes it nice for a change less than 3000 mi., esp. with 170000 and counting on the OD. Any thoughts on mixing honda oil with vavoline when I'm down a quart? Or should I just stick with the off the shelf valvoline?(they're about the same price)

 

I assume your talking about mixing with the same weight oil. In my opinion you should be fine, I just personally wouldn't mix Synthetic with non Synthetic. Supposedly even that is O.K. it just takes away the benefits of using Synthetic, that's all.