OW20 oil in hot climate

Perhaps a 0W-30 would be more suitable? Probably the best thing to do is have an oil analysis done to see how the 0W-20 is holding up under those conditions. Do you have a place that will do that in Italy?

 

Since it's only 2500 meters, I would not worry about 0W20.

 

0W20 is the OEM recommendation no matter the climate. It gets to 117+ here Fahrenheit and I've always used 0W20 synthetic (good for 10,000 miles). Expensive but worth it.

 

For sustained speeds of 130km/h in hot weather with a luggage box on the roof, either 0W-30 or 5W-30 synthetic would be a good choice. You most likely wouldn't have any problems with 0W-20 but 0W-20 would be closer to having a problem than xW-30 under those condition.

 

Yes, the the manufacturers do know. Unfortunately, we as consumers have no way of knowing what the Toyota powertrain engineers would use in their own cars under our individual driving conditions. Do you really think one grade of oil is optimal for all conditions?

 

Gino,
No, the ICE puts out the power required to propel the car. This is no different than non-hybrids.
What the HSD does is allow the ICE to make the required power at the most fuel efficient RPM and Throttle position.
I have an Engine Gauge display and can watch the ICE do its thing.

I read here that the Australian Prius manual calls for thicker oil.
I think the CAFE fuel economy standards make the manufacturers want to use the thinnest possible oil.
It may not be the best for long term engine life. Especially when it is really hot out and you are flogging the car up the mountains.

And why are 5k, 10k mile oil changes such a fixed number?
I think it is the condition of the oil that matters.

I just changed mine at 7k miles, 0-20W Mobil 1, and I wish I had changed it sooner.
It stunk and was darker than expected. I sent it in for analysis. I'll be posting the results.
This oil went through the winter months, which are the hardest on oil. It doesn't get up to temp often enough to evaporate moisture.

This time I used Mobil 1 Extended Performance 5-20W and will try to go the 15k miles claimed for this oil.
The summer months are easiest on oil and I plan on a few Road Trips !!
I'll post analysis of this oil also. Later, much later. If it tests well, this could mean 50% less oil changes in the future !

 

The only problem is you didn't monitor oil temp or oil pressure and only those would give you the answers you are looking for.

 

Actually this is almost exactly what Toyota says in US manuals.

 

Here is a copy of the relevant pages from the Gen 3 Australian Owner's manual, same engine we have. Make of it what you wish. It leads me to believe CAFE Standards, coupled with the EPA rule that the oil viscosity used for mileage tests be the oil viscosity required for use by the customer, are the driving factor for 0W20 oil requirements. However the engine seems to tolerate 0W20 because most of us have been using it for years now with no apparent problems.

 

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I've been wondering about going to 0W30 in the summer. My commute is mostly highway, but I'm not a hypermiler and let the cruise control do its thing, so on some hills the HSI goes into the "power" section for a while. Anyway to monitor oil pressure on the Torque app to see if maybe the 0w20 is thinning out?

 

Thank you. What date or which MY was this manual?

 

To me, when this Prius manual says:
"An oil with a higher viscosity may be better suited if the vehicle is operated at high speeds, or under extreme conditions" , that sounds like any Interstate Highway in America.
And then add really high summer temperatures while climbing the mountains....

It doesn't matter what model year this manual is for.

If you wait until an oil related issue becomes apparent, you now have an engine that has a clatter.

 

It was originally posted by one of our Australian PC members, I can't find the topic right now but as I recall his car was definitely a Gen3 and I think it was a 2010.

 

First, it initially sounded like you asked a question, but in reality you wanted to hear a confirmation of your believes.

Second, oils additives are not needed without specific engine problems. Modern oils do contain boron in balance to other AW/FM agents. If you add more of one agent, the whole will not be necessarily better.

 

Yes, to the 3rd gen. The 2nd gen in Australia is this: http://i35.tinypic.com/29xyx3c.png (sorry, for some reason I can't embed images in PC anymore).

Interestingly, 0W20 was OK in 2nd gen in UK.