Weight of oil for 10k intervals on an '08 w/ 130k (0w20 vs 5w30)?

I would go for 5w-30.

Original speck here is 5w-30 synthetic with 15000km (9320 miles) change interval. It doesn’t get anywhere near cold enough that you would benefit from 0w-20 against 5w-30 in cold start. 130k miles driven (probably with 5w-30) so there is some wear and thicker oil (even though the actual difference between the two is small) is better for worn engine. Fuel economy difference between the two is very minimal.

 

While I'm relatively new to the Prius, I've been building and restoring aircooled Porsches for over 40 years and I've always gone by two rules of thumb:
1. Always go with what the manufacturer lists for that particular car/model. If you ask your question over at Bob is the Oilguy site I guarantee you'll get over 20 different opinions-there are super-thin fans and "thick" fans. IMO you can't beat the opinion of the factory with all of its mechanical engineers.
2. Get the best oil filter available. For the Prius you can get a Denso OEM spec. online for little money or just run down to your Toyota dealer and buy one over the counter. Then grab a jug of M1 from the "mart" and you'll be sleeping well at night knowing you made the best decision.
Bill.

 

The Toyota_USA- recommended drain interval for Gen2 is 5000 miles, which do I go over sometimes (actually often, let's be honest). But there has been some discussion that the Gen2 tends to build up a certain couple % of gasoline in the oil. This is my rationale for why drain interval should not go too too long.

Somewhere in these threads, if I get a chance to search, we have a letter from Toyota_USA stating the 5W-20 is OK for Gen2 as long as you stick to the 5000 mile drain interval. I personally go with Mobil1 5W-30 variations. If I want better MPG, I go to Mobil1 0W-30. If I want to push the drain interval, then the Mobil1 5w-30 Extended Performance (or whatever they call it) is my choice.

My personal logic would dictate, for example, let's say you went with Mobil1 5w-30 Extended Drain now, by the time we got to winter, the oil would be a bit lighter via use. However, if I had to refill in winter, then I might go with the 0w-30 version for the cold weather.

 

If you mostly do long drives and do more highway driving you can use longer oil change interval. On long drives engine gets (and stays) hot especially on highway driving since engine is constantly spinning and this will evaporate gasoline (and moisture) from engine oil.

 

USe 5w30, nothing else.
I would stick w regular ole 5w30 and change it every 5k.