What makes a 10w-30 better than a 5w-30?

[Blue99]

quote:

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BUT if a 5w is better for short trips (5 miles or less) then I have to rethink my oils.

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I think we are trying to split hair, here. M1 5W-30 & 10W-30 are very close in viscosity and will provide very similar results during the start and warm-to-operating temp portion of a driving cycle. Mobil labels M1 5W-30 as more fuel efficient, so a slight edge probably exists over the 10W-30 during the warm-up phase.

If 5W-30 dino is generally considered to provide good performance during engine warm-up, pour points & cold crank data would generate this ranking:

code:

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Good: 5W-30 dino

Better: 10W-30 M1

Better+: 5W-30 M1

Excellent 0W-30 M1

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As far as engine protection, IMHO, any xW oil meeting the ASTM D5293 cold crank max viscosity spec is providing adequate lubrication at start-up.

 

[Drew99GT]

At anything above 20 degrees F, 5w-30 and 10w-30 are essentially the same, with 10w-30 being prefferable because it shears much less. The only time I can see a benefit to using 5w-30 is if you consistantly start your vehicle in temps under 10 degrees F. Your not gaining a thing by thinking that 5w-30 is going to lubricate an engine faster over 10w-30 when the temperature is say, 80 degrees F. Yes, the kinematic viscosity of 10w-30 is still a hair thicker at that temp, but it will flow "realistically" the same. Also, do not forget what Patman and a few others have stated about 5w-30's cold weather performance as it shears and ages: the cold weather performance deteriorates along with the high temp viscosity retention. So, after 3500 miles with 5w-30, it may end up being a 10w-20 or so.

 

[Toyota18]

hi.
mobil1 0w-30, 5w-30 and 10w-30 are not recommended for use in MB cars.only A3/B3/B4 rated oil are recommended.use MB Sheet 229.3 and 229.5 approved oilor A3/B3/B4 rated oil.

 

[Gene K]

quote:

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Originally posted by Toyota18:
hi.
mobil1 0w-30, 5w-30 and 10w-30 are not recommended for use in MB cars.only A3/B3/B4 rated oil are recommended.use MB Sheet 229.3 and 229.5 approved oilor A3/B3/B4 rated oil.

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Mobil 1 0W-40 meets MB 229.5
Amsoil 5W-40 meets MB 229.5

Both are on the MB approved oils list.

Mobil 1 15W-50 is A3/B3 but I do not believe it
meets 229.5.

Gene

 

[G-MAN]

quote:

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Originally posted by Gene K:
Amsoil 5W-40 meets MB 229.5

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Sure it does.

 

[Gene K]

quote:

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Originally posted by G-Man II:

quote:

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Originally posted by Gene K:
Amsoil 5W-40 meets MB 229.5

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Sure it does.

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DO NOT USE AMSOIL IN THE USA! SORRY!

What the @#$% your right G-Man II!

I just checked the M-B 229.5!

It is Approved everywhere but the US!

I guess since the ACEA tests are done by the supplier and no paperwork has to be filed M-B World wide has approved Amsoil 5W-40 "European Car Formula". My guess is that M-B USA wont approve it because it isnt API certified and they would run afoul of the EPA!

First 5W-20 and now we cant use USA made M-B approved oil because of the @#$% EPA NAZIS!

Gene