Difference between SM & SN

[Boss302fan]

SM, SN, GF 4 and GF 5 are all good oils. I highly doubt any of us could ever tell any difference between them.....

 

[OldCowboy]

The best oil is one that is SN/GF-5/dexos1.

The dexos1 spec requires better capabilities in seal compatibility, corrosion protection, volatility, engine sludge protection, piston cleanliness, turbocharger protection, oxidative thickening and wear protection.

Of course, dexos1 only applies to 5W30 grade oils.

 

[addyguy]

A lot of SN-GF-5 oils are somewhat thicker than their SM/GF-counterparts.

Cold-weather performance has gotten worse with SN/GF-5 oils - cold-cranking values have risen on almost all oils.

Also, as we all know, all oils have gotten much more expensive.

SN/GF-5 is NOT an improvement, it's just a cash grab by the API.

 

[ernied]

whats really wierd is both of my hyundais call for 5/20 gf3 or better.i guess oil really does not matter in them.

 

[Bamboooo]

Thanks everyone. This makes the water a little less muddy! I have some QSUD 5w-30 on the shelf that is SM rated. Is it safe to say, that just because an oil isn't rated SM, doesn't mean it doesn't meet the SM standards?

 

[ZeeOSix]

Originally Posted By: OldCowboy
The best oil is one that is SN/GF-5/dexos1.

The dexos1 spec requires better capabilities in seal compatibility, corrosion protection, volatility, engine sludge protection, piston cleanliness, turbocharger protection, oxidative thickening and wear protection.

Of course, dexos1 only applies to 5W30 grade oils.


Here's the spider web diagram that shows the dexos 1 compared to the GF-4 and GF-5.

http://www.gf-5.com/gsuniverse/sitetemplates/gf5/SPIDER DIAGRAM.html