Does motor oil brand make any difference for the Prius?

as long as the specs are correct, it is a well respected manufacturer, and it is pure synthetic, it shouldn't matter.

 

How many miles on it?

I've used just Toyota 0W20, mainly because it's cheap and convenient, I'm at the dealership anyway to get the filter and drain bolt washer. Also, I'm buying it in bulk container now: even cheaper, and no empties to recycle.

I'd concur with bisco; they're all doing the same job.

 

That will accomplish exactly nothing.
The "base" viscosity is still 20. The 5W will just be a tiny bit thicker when cold; when hot, no difference.

And those who are telling you not to use a thicker oil are NOT doing you any favors.
Something like a 15W40 high mileage oil will NOT harm your engine in any way.
It should slow down the oil loss........for a while......but won't really "fix" anything.

 

I would probably start with lowest visc Mobil 1 High Mileage which is probably 5W-30.
But I'd stick with well rated brands whatever they are Toyota, Pennzoil, Mobil 1, etc.

 

I don't think brand makes any difference. What matters to .e, would be, is the brand in question even following the specifications laid down by Toyota?

 

Different brands of oil have detergent cleaners and friction modifiers in them while some do not, there is also different flash points. #w is the cold start oil viscosity. w# is the warm operating temp viscosity. When cars start to burn oil, people tend to bump up from 0w20 to 0w30 and 0w40. In cold people like to run 0w and in summer people like to run 5w. Cars will consume oil is several ways, Leak (outside engine), worn valve seals (burns oil in engine), worn rings (burns oil in engine) and pcv (sticks open/shut). The pcv valve is often overlooked and with increased blow-by can lead to more oil being burning in though the intake manifold and into the combustion chamber. The prius has a poor pcv valve design in my opinion and to combat this, an occ (oil catch can) prevent a lot of this oil/water/fuel to enter the combustion chamber to be burned. When excessive amounts of oil/water/fuel are burned in the combustion chamber, rings tend to coke up to not properly lubricate cylinders to increase engine wear. It can also lead to increasing compression and cause engine knock at start up. This knock/compression increase will blow a head gasket. The occ will help keep the engine clean. Burning oil in the combustion chamber coats carbon deposits on valves, pistons, heads, egr circuit (cooler, pipes, intake plenum) catalytic converter and so on. I also think the 10k oci (oil change interval) is bad for the car especially in the winter when more moisture and fuel are in the crankcase breaking the oils viscosity down, creating more engine wear and pushing oil through the pcv valve system. In the cold weather I do 5k oci and in summer I do 7.5k oci to lengthen the life of the engine. The motor new was designed to run on a 20 weight oil and as those main/rod bearings, valve guides, cams etc wear out. A thicker oil can compensate for the loss in displacement. I do not think running thicker as the engine wears is bad for the engine. Running 20 weight oil on an engine that has 250k+ would not protect the components as well as a thicker oil would. I would start with changing the pcv valve and run a 0w30 weight oil and do a 5k oci for the winter and then run a 5w30 for the summer and check the oil level weekly to see your progress. I highly recommend you install an occ, you will be able to monitor how much oil/water/fuel is passing through the pcv. Fossil fuel burning cars are dirty. We will call them fossils when all electric comes out.

Here is a pic of a prius with excessive amounts of oil being burned in the combustion chamber with a blown head gasket.

 

I guess that's not going to "buff out". Would they ever fill that with weld, or is that just crazy talk?

 

There are good machinist that fill em up to the required thickness and all that.

I have done similar stuff on a highlander top cylinder head before.

Car still runs cool, till today

 

That's the problem. If what the brand tells you is inside the motor oil is one specified for say, a 1NZ engine, then I'd go for it. Except, maybe, if there had being reports from other users that issues have sprang up from their usage of such brands.

 

Look for the starburst and donut symbols on the package, or check the API EOLCS database, as described in my previous posting. This was in the fourth-generation Prius forum, but the information also applies to the third-generation Prius, which has the same oil specification (SAE 0W-20, ILSAC GF-5).

 

This is the meaning of Toyota's oil specification.

You can find these specifications on the back of your oil can/bottle.

ILSAC GF-5
Introduced in October 2010 for 2011 and older vehicles, designed to provide improved high temperature deposit protection for pistons and turbochargers, more stringent sludge control, improved fuel economy, enhanced emission control system compatibility, seal compatibility, and protection of engines operating on ethanol-containing fuels up to E85.

 

I still think the reason for 0w-20 is just for fuel economy. I agree with using 5w-30. When you look up recommended oil in other hot weather countries like Australia 5w-30 is recommended.

 

3rd gen Canadian interval with 0W20 is 6 months or 8000 kms (~5000 miles). 4th Gen, they match the States. I'm skeptical of their decisions, motivations, even the oil grades.

 

Rated by whom?