WSS-M2C931-A vs WSS-M2C931-B

[KDS]

Whats the difference? I couldn't find it any place.

 

[saaber1]

Hey, what are all those numbers and letters?

 

[Johnny]

Ford?

 

[KDS]

Sorry I should have put that in the title, they are Ford Oil specs.

 

[rharris]

KDS, I found this entry on the http://www.teamshelby.com message board via Google search. I hope it helps.

WSS-M2C931-A is essentially SAE 5W-50 API SL. WSS-M2C931-B is essentially SAE 5W-50 API SM. Both have a few other characteristics beyond SL or SM. The change from A to B was to upgraded to the latest catagory.

I can't explain why no one else wants to claim these specs. These specs do have a lower phosphorus limit than what is required for SL or SM, for catalyst compatability. So this may be why similar viscosity grades can't claim they meet these specs.

Hope this answers your questions.

Thanks
Ron
Service Lubricants Technical Expert
FCSD, Service Product Development, SEO
Diagnostic Service Center II

Ford/Motorcraft MSDS Help Desk

 

[bdcardinal]

i stock a couple cases of it, we have a fair amount of GT500s that come in for oil changes and a few GT Supercars. the stuff isn't cheap, thats for sure. i can post pics of the bottles if you want to read the fine print.

 

[roushstage2]

Basically, in addition to rharris' post, -A is GF-3 and -B is GF-4. Really about all there is. Just a really technical way to say what oil you should use.

 

[KDS]

Thanks guys. Does anyone know if anyones tested the ROUSH/Valvoline oil vs Motorcraft?

 

[bdcardinal]

a few guys on SVTP have used it on their GT500s, although i think cost is similar.