new (not really) oil from mobil 1, 0w-30 and 0w-20

[Inspector14]

i am apprehensive about using a 0w-30 in the summer. i would like to use the castrol syntec 0-30 (good german stuff) just not sure if 0w-30 is too thin for the engine when cold?

[R2D2]

Originally Posted by Inspector14

i am apprehensive about using a 0w-30 in the summer. i would like to use the castrol syntec 0-30 (good german stuff) just not sure if 0w-30 is too thin for the engine when cold?

0W-30 is certainly not too thin. In fact at room temp GC is slightly thicker than Mobil 1 5w-30 (66.8 vs. 64.8 cst, respectively.) The first number in the viscosity classification is a number that indicates the oils relative performance in the cold-most specifically cold cranking. It will be about the same thickness at operating temp as a 5W-30 or a 10w-30. (See second link below).

Here are some links to some info I originally passed on to DerFlosser when he asked a question about seasonal oil changes. The second link provides a link to a series of papers that is a goldmine of information about viscosity and hopefully can clear some of the confusion regarding oil viscosity classification.

http://www.yarisworld.com/forums/sho...46&postcount=3

http://www.yarisworld.com/forums/sho...21&postcount=7

You should be OK with a 0W-30 as far as warranty because they do not warn against it and other than cold crank specs the viscosity is almost identical to a 5W-30.

My first choice would be a 5W-20 in the Yaris REGARDLESS of environment, ALASKA or TEXAS. I would recommend 0W-20 post warranty but would not use it under warranty because the TSB specifically warns against it (which makes no sense).

R2

[1stToyota]

Mine's a '08...just curious; my cap and owner's manual states 5w30, then comes the TSB, what's the '09 oil caps and manuals say now?

[DevilGirl]

Originally Posted by 1stToyota

Mine's a '08...just curious; my cap and owner's manual states 5w30, then comes the TSB, what's the '09 oil caps and manuals say now?

I believe mine (09) also says 5w30. I havn't looked under the hood lately though...

[R2D2]

Originally Posted by DevilGirl

I believe mine (09) also says 5w30. I havn't looked under the hood lately though...

Ditto-they still say 5w-30 on my 09 cap and in the manual. The only reference to 5w-20 I've seen is the TSB and it lists the NZ series. I keep a copy in my glove box.

[1stToyota]

Originally Posted by R2D2

Ditto-they still say 5w-30 on my 09 cap and in the manual. The only reference to 5w-20 I've seen is the TSB and it lists the NZ series. I keep a copy in my glove box.

Then Toyota isn't taking their own TSB too seriously, it seems.

[DerFlosser]

Originally Posted by 1stToyota

Then Toyota isn't taking their own TSB too seriously, it seems.

Well....I wouldn't go that far. It's likely that they signed up with a vendor to make the caps and they probably made up millions upon millions of these with 5w-30 screened on them.

[Yaris Hilton]

Originally Posted by Inspector14

i am apprehensive about using a 0w-30 in the summer. i would like to use the castrol syntec 0-30 (good german stuff) just not sure if 0w-30 is too thin for the engine when cold?

The second number is the SAE viscosity rating at 210 degrees F. The first one with the W after it is the viscosity at 0 degrees F. NO current oil thins out at lower temperatures or thickens at high temperatures. They all thicken in the cold and thin as they get hot. The oils with wide spreads between the two numbers just change viscosity less with changing temperatures. The great advantage of the oils that don't thicken rapidly with falling temperatures (which is what the 0W tells you) is that they circulate rapidly in the engine on startup in very cold weather, which an oil of higher cold viscosity may not do.

[Henry G.]

Thanks for the link, good to know. Just can't figure out either why they put the TSB out in '06 and my '08 still calls for 5w-30? I may try the 5w-20 in the winter.

[Yaris Hilton]

They didn't change their primary recommendation of 5W-30. They just said it's OK to use 5W-20 (which thins out more as it gets hot.)

5W-20 isn't any better in cold weather than 5W-30. They have the same viscosity at 0°F. The 5W-20 thins out more at 210°F than the 5W-30 does.

[1stToyota]

Originally Posted by Yaris Hilton

They didn't change their primary recommendation of 5W-30. They just said it's OK to use 5W-20 (which thins out more as it gets hot.)

5W-20 isn't any better in cold weather than 5W-30. They have the same viscosity at 0°F. The 5W-20 thins out more at 210°F than the 5W-30 does.

I use Pennzoil Platinum and found it odd that their 5w-20 had an ACEA rating of A1/B1, but their 5w30 is ACEA rated at A5/B5, which BTW is equal to the Amsoil High Performance 5w30 that I used to use, except the PP gets API approval.