I took my recently purchased 2013 base Prius (leased car originally) in for it's 4 month certified check. They rotated the tires, and did some checking (fluid levels, etc.) , but did not change the oil. The technician said the car had synthetic oil and would not need an oil change for 10K miles. I drive only about 500 miles/month, and I normally got an oil change every 6 months on my 08 Prius (in the pic). He scheduled me for April. The '08 Prius uses regular oil. I checked my '13 manual, and the oil spec is OW-20. No mention of synthetic. So I googled the car model, and found every Prius has synthetic oil in 2013 (earlier years as well). But no mention of "synthetic" in the Prius manual! Confusing. You have to know OW-20 is synthetic.
Most current engines running full-synthetic oil don't need oil changes sooner than 10K miles. A lot of that is the quality of the oil.
If you read the Toyota Warranty & Service guide (a separate booklet) carefully, you'll notice that Toyota makes no mention of synthetic motor oil. What they do say is the you can go 10,000 miles on 0W-20 oil. If you don't use 0W-20, then they want you to change oil at 5,000 miles.
First, a clarification: the official 3rd gen US oil change interval is 10,000 miles or 12 months, whichever comes first. Some thoughts: 1. I agree, Toyota makes no mention of synthetic. All they spec is an oil grade to use. Around the world they spec more grades than just 0W20, still I think the recommended grade is 0W20. There's a few owners here that are regularly putting in 5W30, no problems. 2. If you're concerned about the long US oil change interval, keep in mind: it's your car, not the service writer's. To put his mind at rest (chuckle), you could mention "severe service". This doubles up the miles and time interval, to 5,000 miles or 6 months, per your 2nd gen. FWIW, Toyota Canada specs 8,000 km (~5,000 miles) or 6 months for 3rd gen. I'm similar mileage as you, actually more like 500 kilometers monthly, and every 6 months, it's (DIY) oil change time. For me it's a couple of hours chore, and about $30 in supplies. Keeps me occupied. FYI, Toyota Canada has gone to the US oil change interval (16,000 km or 12 mo) for 4th gen Prius.
0W-20 is only available as a synthetic or synthetic blend oil; by specifying the weight, Toyota has already specified a synthetic oil.
