I have a 2008 Toyota Prius.

I've looked at the manuals:

Neither mentions synthetic oil at all.

The Scheduled Maintenance Guide recommends changing oil and the filter every 5K miles but is probably talking about standard dinosaur oil.

These 3 sites recommend 10k but don't mention Prius in particular (or hybrids), so I'm hesitant to blindly follow them because I don't know if that makes a difference:

https://www.toyotaofsantabarbara.com/prius-recommended-maintenance-oil-change.htm says "Some model year Prius may have Synthetic Oil and only require an oil and filter change every 10,000 miles or 12 months." (No other details.)

https://priuschat.com/threads/how-often-do-you-change-your-oil.84594/ has a bunch of anecdotes with no official documented recommendation.

  • So 4 separate sources for Toyota and synthetic oils have a 10000 mile change interval. What are you wanting? a site just for your car with the registration and vin specified? I used synthetic oil and doubled the mileage but changed the filters twice as often...
    – Solar Mike
    Feb 11, 2019 at 16:31
  • 10k is pretty LOW these days, except for US cars running on dino pee. My 10-year-old Fiat has an 18k oil change interval, and it only burns half a litre (= half a quart) in between changes.
    – alephzero
    Feb 11, 2019 at 17:21
  • @SolarMike As emphasized in bold, I've been hesitant to follow generic recommendations about Toyota because I don't know whether the fact that it's a Prius (hybrid) matters. Lots in the Prius manual cautions against treating a Prius the same as other cars.
    – Ryan
    Feb 11, 2019 at 17:24
  • Then don't, follow the Prius instructions EXACTLY and don't mess around with different oils or even other makes of tire.... Also make sure you only take it to a main Toyota dealership for maintenance / repair.
    – Solar Mike
    Feb 11, 2019 at 17:25
  • In theory, synth oil will last forever (without degrading). However, all oil gets dirty (sludge, water, metal bits, etc) over time. Getting an oil and filter change every 10k miles or once a year is very very very smart.
    – sam
    Feb 12, 2019 at 23:53

2 Answers 2


https://toyota.custhelp.com/app/answers/detail/a_id/7604/~/what-are-the-oil-change-intervals-using-synthetic-oil%3F seems to be an official Toyota page (although hosted by Oracle), and although it doesn't mention hybrids or Prius in particular, at least it mentions synthetic oil:

What are the oil change intervals using synthetic oil?

  • Only Toyota vehicles in which 0w-20 synthetic oil is required (except 3UR-FBE Engines*) have been approved for extended oil change intervals of 10,000-miles/12-months. (However, you should continue to check the oil level regularly and top off if needed. That will help your engine get the full benefit of synthetic oil.)
  • Vehicles in which 0w-20 is an option to 5w-20 mineral oil, (or 5w-30), will continue to require 5,000-mile/6-month oil change intervals, even if 0w-20 oil is used.
  • In the case of vehicles with 10,000 mile oil change intervals, the 5,000 mile service interval has not been eliminated. The traditional 5,000 mile maintenance procedures (such as tire rotation) will continue to be required, and the fluid levels (such as brake fluid) will need to be checked and adjusted at this time.
  • If the vehicle operation meets the standard criteria for "Special Operating Conditions" such as: driving off-road, on dirt roads, towing a trailer, making repeated short trips under 32˚ F, or extensive idling; the engine oil must be replaced at 5,000 mile intervals, regardless of what type of oil is used.

*The 3UR-FBE (Flex Fuel Tundra / Sequoia) are the exceptions to this new change interval program; these engines have not been approved for the 10,000 mile interval at this time. A 5,000-mile/6-month oil change interval is still required for these vehicles. Also, the Flex Fuel 3UR-FBE requires a 2,500 mile interval when operated on E85.

  • Most people don't realize it, but (at a SWAG) I'd bet 90% of all vehicles on the road today fall under the fourth point (shorter change interval) with one of the factors mentioned being present. No hard data (and my GoogleFu isn't strong this morning) on this but it seems I've read about this somewhere before. Feb 13, 2019 at 16:07

Where I live, most Toyotas have 1 year / 15000 km (approx. 10000 mile) oil change interval. For my 2016 Toyota RAV4 hybrid, a much newer car than 2008 Prius, only ILSAC GF-5 multigrade engine oil is specified. The only "synthetic" word usage in the user's manual is about synthetic leather.

There are mineral oils meeting the ILSAC GF-5 specification (this one is 5W-30, my car uses 0W-20): https://www.penriteoil.com.au/products/premium-mineral-5w-30#/

I don't think your car requires synthetic oil. Just use Toyota genuine motor oil or if not available, another oil meeting the specifications mentioned in the user's manual. A 2008 Prius, where I live, can perfectly well function with 1 year / 15000 km oil change intervals without synthetic oil.

Your car is out of warranty, and there's no hope in getting any compensation from Toyota if the engine breaks. Thus, I would be lazy and extend the oil change interval to 1 year / 15000 km, using the specified oil quality. I don't think that's going to break the car.

The half year / 5000 mile oil change interval has probably been decided by some local dealerships that just want the extra revenue from changing the oil often, in an area where frequent oil changes are the norm. Where I live (Finland), nobody would accept a half year / 5000 mile oil change interval.

The comment by Paulster2 still applies: if you do frequent short trips in cold weather, there may be some benefit in halving the oil change interval to half year / 5000 mile interval.

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