What kind of oil!?

If you change every 5000 miles then I would use 0-20 regular oil. Maybe Toyota brand? Synthetic 0-20 maybe double the mileage? Something like Mobil1, Pennzoil platinum, Aimsoil. Hal

 

Do you know if the original owner used regular oil or synthetic? If synthetic was used by the previous owner, I would continue using it. If you plan on changing the oil at longer intervals, I would use synthetic. Otherwise dino oil works great!

 

It sounds like the engine was well maintained. I use Mobil 1 0W-30 all year round. It only takes approx. 3.5 qts so any good brand of oil will do and not cost too much...esp if you continue 5K intervals. Amazon has good Purolator filters for $5.00 each
Purolator PL14476 PureONE Oil Filter, Pack of 1

:cheer2:

 

5W-30 is the recommended viscosity in the US. The choice between synthetic or mineral is up to you. If you observe 5K mile engine oil changes then a quality mineral oil is sufficient. I observe 7.5K mile oil changes using synthetic oil.

If you use 0W-20 you may realize a 5% mpg improvement. However my 2004 started to consume substantial engine oil when I made that switch, and this continued (although at a reduced rate) when I moved back to 5W-30. Since your car already has logged 119K miles I think your engine may be at risk for that as well.

 

what does your owners manual recommend?

 

I think so, this is why I buy it.

 

Just use what the owners manual suggests. You could go the synthetic route but considering the increase in oil prices lately, that might not be your most cost effective option.

Personally I'd go with the least expensive oil I could find, making sure it's the correct weight. Then use a quality oil filter, maybe even replacing the oil filter more frequently.

 

For this oil change, just get a jug of SuperTech 5w30 oil and a SuperTech filter at Walmart. That gives you 5,000 miles to research the option that is most comfortable for you. These engines run an incredibly long time without failure, so by far the most important thing is to just have halfway decent oil installed. On the synthetic side, there are people here going up to 20,000 miles here on Mobil 1 0W20.

 

If you don't have the correct model and year Owner's Manual, buy one from a dealer. It's full of stuff that you need to know.

 

I'm really impressed. This is the first time I've seen an oil thread being so civil. Everyone here is correct there is a range of what you can use at the opposite end of the range I'm using 0w 40 in Florida. In my mind I justify it because I hold the throttle pinned wide open for extended periods of 5 to 10 minutes I also find that this oil does not burn out. I'm not noticing any oil consumed. 0 W 20 used to burn out of this engine at a rate of 1 quart every 800 miles when pulling a trailer. Now I don't burn any

 

2005 Toyota Prius Owners Manual and Warranty - Toyota Owners

I'd personally use a good quality 5w30 and get some filters from Amazon and stick with a 5K OCI.
I personally use Castrol, NOT because I presume that it's THE BEST oil out there, but rather because it offers a good balance of performance versus cost, and because it is and has been widely available.

I've worked in your field for many years, and there are a lot of principles of electronics troubleshooting and maintenance management that work exactly the same way that they do in automotive maintenance management, troubleshooting and repair.
Your car is going to be a teenager next year, and like most teens it might start to act up a bit from time to time.
Also......like most teens, it might start smoking and drinking a little bit if you're not paying attention YOURSELF instead of farming those duties out
to others.
The link I sent you has maintenance guides and the owner's manual for your car.

For the 05 it's pretty easy.
As Patrick said, they only recommend 5w30, and they recommend that you check your oil level every time you load fuel.
Since virtually nobody does this in 2017, Toyota now recommends you check your oil level every month or 1,000 miles.
Virtually Everybody who has lubrication related engine trouble fails to do this.

Personally?
I'd go with the OEM recommendations on this one, but YMMV.
There are a lot of people with very strong opinions about viscosity, blends, and synthetic versus dino.....and most of them are right most of the time....meaning most of the time it really doesn't matter all that much in the end.

Since the recommended OCI (oil change interval) for a 2005 is 5K


You're asking all the right questions.
Good Luck!

 

Its always best to use the weight the user manual asks for and for the 2nd gen It's 5w30. I used the full synthetic at first but it was dripping oil after (it is best to start a new car on new synthetic and always stick with it, and adding full synthetic to any higher milage car takes slidge depoisits out around rings which are actually preventing leakage. Since it was so light weight it ran fine but in the hottest part of summer I could hear some more friction than I do now after I switched. I use castrol 5w30 high milage synthetic blend. There is no leakage, the engine sounds very smooth, and change it every 4000 miles. I use only toyota oil filters as they trap oil purges it to the engine faster leading to reduced wear on start ups.

 

Interesting! Never heard of anyone using 0w40 in their Prius before. How does it run with that oil? And where do you buy it?

 

Mobil 1 at Walmart. I get it for r $13/5 qt jug after mail in rebate. I burn about 1qt/10k mi. I pull a trailer 500mi/20k mi driven. I used to burn 0-30 at an alarming rate but not as bad as 0-20. I also run this engine wot for up to 10 minute periods. I feel pretty certain that I'd spin a bearing if I did this w 20wt oil but who knows.

I got it w 120k and now have 190k. It's still quiet. Toyotas are awesome

 

Extended uphill climb?