Prius 2010 oil change advise (urgent)

I'd always suggest going with what the manual says. In the US, Toyota recommends 5W30 oil. My assumption is that the oil recommendation for Fiji is based on the car's performance in your climate.

 

US spec is 0w-20 not 5w-30.

OP, what do you mean by "experienced low performance"?

You will be able to use 30 weight oil, at a loss of some mpg efficiency. However, some people use 30 weight oil to offset oil loss/burning in higher mileage vehicles.

 

Wonder if that oil loss is due to overfilling. I find it irritating how on our '04 Sienna if I put in 5 qts as noted it is slightly over the top marker.... The manual should have the weight, as well as operating ambient temperature range. Just as an FYI understand that the oil experiences much higher temps than any possible ambient temperature that we could possibly survive. You should be fine with the recommended weight. They don't note anything special. Death Valley is not too far from where I live...

MT2L03 ?

 

Oops, I wrote down oil spec for gen 2 Prius, not gen 3.

 

In the US, and Canada too, for a 2010, Toyota recommends 0W20.

That said, in a tropical climate, staying with second gen specified 5W30 is maybe not a bad idea. I wouldn't stress over it: there are a few North American 2010+ owners using 5W30, to slow or forestall oil consumption. And plenty more tropical owners, where 0W20 can be difficult to find.

If you're having a hard time finding specialty grades, the very common 10W30 would be fine too. It will impact mpg slightly, but not a big deal. Here's an excerpt from the Autstralian Owners Manual, with oil recommendations, for a counterpoint to the North American specification:



It's a poor copy, but in the above, the three centigrade values at left end of chart appear to be negative values, extreme cold.

 

I use 5w-30 full synthetic. I have 147 k miles on our 2010 Prius II and switched to slightly thicker oil to slow the oil consumption. It works!

I have not seen a measurable loss in mpg, as there are other factors that contribute to mpg loss that are more significant IMO.

How many miles on your Prius?

 

The lowest weight I would run is 10w-30. Also get a good synthetic if you can. It should have a higher volatility temp. Generally, the less the numbers spread i.e 5w-30 versus 10w-30 the less VIIs are in the oil (viscosity index improvers). VIIs will shear over time and heat giving a thinner more volatile lube.

So start with 10w-30 and if your oil consumption is low stick with it otherwise try a 15w-40.

Posted via the PriusChat mobile app.

 

0W-40 in my Prius in the summer. Mobil1

 

The lower the oil's weight, the thinner it is. This means that the moving parts inside the engine can move with less resistance. This is why the 0w20 delivers highest gas mileage.
As the oil's weight increases, it thickens. But this also delivers better performance when it is hot, because the thicker oil can stick to moving parts better and keep them lubricated.
Since Fiji is so hot and never freezing cold, a thicker motor oil is better. I purchase Mobil One, but I don't know if you can buy it in Fiji.

 

+1
You also need to consider the change interval.
In order to keep the same recommended change schedule, you need to stick with a synthetic oil.
I think most 5W30 is but maybe not all.

Just out of curiosity, what does your local dealer say about this.......if you have a local dealer.

 

I'm sorry but I find that impossible to believe........unless the cars in question have REALLY high mileage and/or are driven REALLY hard.
The main reason for such a thin oil recommendation is to squeeze the last hundredth of a mile per gallon out of the efficiency ratings.
A small step up in viscosity, like to a 5W30 full synthetic should have no noticeable effect on anything.

 

To repeat:
You need to stick with a fully synthetic oil......OR you need to change it more often.
I think that 5W30 would be your best choice IF it is synthetic.

 

Priuses are liquid cooled and controlled by a thermostat, which is why all of the arrows on the viscosity versus temperature chart point to the right.
Put another way......
It doesn't matter how hot and humid it gets in Fiji, your motor will be just as cool and comfortable on the inside as the ones in Canada during the winter.

THE REASON you're suffering from poor performance in Fiji is that you live in a wonderful place to do many things except take long drives.
The gasoline in your islands may also be a little different than it is in other markets.
In other words, all of your trips are relatively short, and I'm sure that you use the HVAC more than people who have to suffer living in more temperate climates.

Go with the factory recommended oil.

Good Luck!

 

I switched to 5w-30 full synthetic from 0W-20 full synthetic and experienced no issues. If that is what is available at the dealer, use it.