MPG Difference of 0w20 vs 5w20

I don't think Toyota's ever said 5W20 will harm the engine. They actually spec a wider range of weights in some parts of the world. Australia for example. Maybe turn it around: try it, report your findings?

Alternately, and in your shoes this is what I'd do: just unload your 5W20 with someone still using it?

Not my business but anyway: I use the "just in time" approach, when shopping for oil, filters, etcetera. Just get what I need. Dealerships (up here at least) sell Toyota 0W20 dirt cheap, single liters for $5.63 (canadian). No need to chase sales, coupons, or to stockpile.

 

You are correct to assume negligible difference between 0W-20 and 5W-20 what does it say on the oil cap (5W-20?)

 

Practically no difference for gas mileage at temperatures above freezing. Big difference though is in service life - I would change dino 5W20 in 3000 or 5000 mi at most, while synthetic 0W20 should be good up to 10 000 miles

- Alex

 

If you used 5w-20 before and didn't have viscosity issues, you shouldn't have any issues with the Prius. If it were my car, I wouldn't hesitate using 5w-20 dino. Just change it out at 5000 miles.

 

I agree I would do 5000 miles if it's Dino oil follow assuming the gen3 manual says synthetic is needed for 10000 mile drain Interval

 

The Toyota website does say that OCI is 5k for dino oil.

 

There is 5W20 synthetic, just saying.

 

On my 2010, the earlier oil changes (before 30k), the dealer just puts on there "oil change". No parts listed. After 30k, the oil changes actually had 5 qts 0w-20 listed......so what they hell did they give me prior to 30k? bulk 5w-20 dino?

 

I don't see any mention that if 5W-20 is used, the next oil change interval should be sooner, just says to go back to 0W-20, at the next oil change:



The above's from the North American Owner's Manual. And from the Repair Manual:



The inclusion of 5W-20 grade for Canada (at least in the Repair Manual), and exclusion for the States, has me scratching my head: seems like it's mpg requirement more than climate, driving the decisions.

 

IIRC, it had to do with conventional vs synthetic, not viscosity.

 

The Owners Manual doesn't make any distinction.

 

I guess I was thinking about this (from FAQ section), it does not specify that the OCI is is shortened from 10k to 5k.

What should I do if 0W-20 synthetic oil isn't available?

If SAE 0W-20 synthetic oil is not available, SAE 5W-20 conventional oil may be used. However, it must be replaced with SAE 0W-20 synthetic oil at the next oil change.

 

I doubt running conventional oil one time for double the mileage interval is going to cause any meaningful harm.

 

interesting, maybe this is why some people get oil consumption in prius under 100,000 miles?
a few years ago VW dealerships did that swichero a lot, some engines got sludged and VW had to cough up warranty money, but the dealerships got away with doing it. my friend has a VW that gulps oil serviced only at a dealership.

 

yes my 2010 burns oil, now at 75k miles, it burns about 1 qt every 3000 miles. It's only been dealer serviced up until 50k miles. Not really sure what causes the oil burning though

 

if i were you i would do some nice engine flush session during the next oil change.