I'm debating which oil to use during my next oil change; i know none of them can harm the car in any way.
so here are my choices:

1. Mobil 1 5W30 ( I currently run this) - no difference between this and regular non synthetic oil toyota uses.

2. Castrol Syntec 0W30 ( I use this in my BMW, it's green and it says made in germany) not that it makes a big deal

3. Mobil 1 0W20 (I just started seeing this, maybe it's new and perhaps some toyota dealers are using this)

They all cost the same at a local store near my home except the
castrol costs about a dollar lower at $7.50CAN.

luckily the prius only holds about 3L to be right at the middle mark, so changing oil doesnt cost a fortune.

any comments or advice is greatly appreciated.

Neither. I would go with 5W20, its what toyota is recommending for 2006 NZ series engines. People have had good results with Mobil 1 gold cap but I'm not sure if they make 20 . Of course just my opinion...

Thanks for the reply,

I think the first number (0W or 5W) refers to the viscosity at startup, the lower the number the easer for the engine to crank itself,therefore, greatly reducing wear and tear. So having said that, wouldnt it be better to buy an oil with a 0W instead of a 5W to greater reduce wear and tear? As soon as the engine warms up, the second number is what's significant throughout the rest of the drive. I know the manual recommends 30 weight oil for the prius, but interestingly, i logged on to the canadian website and consulted the maintenance page and this is what i found out:



Near the bottom it says 5W20 and 5W30 motor oil only.

I spoke to someone at a local dealer about this and he denied toyota recommending this oil to them


So my quesion is, has anyone used 20 weight oil for their prius with no adverse effects?
if yes, then i'll go and pick up 4L of 0W20 Mobil 1 oil today. The 5W20 is not available here, i havnt seen it anywhere.

The first number refers to the actual weight of the oil. Now think of butter when it gets hot, it thins out to a lower weight. To counter-act this, scientists added "glue" to the mix that thickens the oil when hot. The second number represents the weight of the cold oil that its chemically represents. In other words a 5W30 oil hot is thinning out like a 30W oil would when hot.
As for what weight is best... Too thin it burns up, too thick it bogs the engine down. What the manufacturer recommends is whats best, they know the engine best. Here's a link to the TSB regarding recommended oil for Toyota vehicles
http://www.alldata.com/tsb/Toyota/11...-06/index.html

The 2006 Prius has the NZ series engine I believe. Check your manual to be sure.

Check your oil level after putting in 3L. I suspect you'll find it is perfect and 4L puts it 'over the top.'

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

i forgot to mention

I'll buy 4 One Liter containers, Use 3 in the engine and keep one as a top off spare

i'm still debating which oil to use. right now i'm leaning towards
Mobil 1 0W20 or Castrol Syntec 0W30, i've read somewhere that mobil tends to make their oils a little thinner than castrol. for example, the mobil 0w40 is on the lighter side of the 40 weight and is closer to 30 weight. On the other hand castrol syntec oils tend to be on the heavier side; their 5W30 is on the heavy side of the 30 weight and is closer to the 40s. This is why most BMW (E46) owners use Mobil 1 0W40 instead of the recommended 5W30 Castrol Syntec oil. Either that, or they use Castrol syntec 0W30 german green oil because it's perfectly weighted at 30, however, this oil is not available everywhere where i live and the Mobil 0W40 is only available at mercedes benz dealers for $9/L.

I'd be glad to try the castrol Syntec 0W30. I'm not buying the oil primarily for fuel economy, but more for protection for my engine. I dont want to end up buying oil which is too thin which can fail to reach all the places in the engine.

any comments or suggestions are greatly appreciated.

thanks,

gj

Good plan. I think I'll add it to the FAQ.

I wish I could help but I've only done one ICE change with Mobil 1 5W30. I'll be sending sample for testing but my plan is to clean the pan and fill with Amsoil 5W30. Alabama is a lot warmer than your neck of the woods so we like a little higher viscosity. IMOH, going down 5 viscosity points makes sense in areas with long cold winters.

GOOD LUCK!

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

While I don't like succumbing to advertising, Mobil is recommending 0W20 specifically for newer Hybrids that use 5W20.

http://www.mobiloil.com/USA-English/...l_1_0W-20.aspx

Be careful in what you read and how you read it.... Toyota TSB EG050-04 for the years 01-06 Prius's states the 'Recommended Viscosity" for the Prius per this Toyota TSB is 5W-30.

TSB # EG018-06 is for all 'OTHER' Toyota vehicles and even states for Prius vehicles refer to the TSB EG050-04 as mentioned above.

Continue to use 5W-30 for your Prius.

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