I was calling around to get a good deal on motor oil(5w20), and I found out about specs. The specs for my truck, which I got from a guy from Advanced Auto Parts, didn't know what it meant exactly. But on his computer the 5w20 spec included: WSSM2C945A. I'm not really sure if that is important or not. But seems like it will be a little hard finding it exactly, and at a good decent price. For any vehicles I've owned in the past I've only gone off the winter and viscosity numbers. Should I be concerned with this WSSM2C945A spec number? Thanks in advance.

 

no.... just get the 5W20 spec with the latest "SP ... or SN " code


What the "S" code signifies

• "S" (Service/Spark Ignition): Indicates the oil is formulated for gasoline-powered cars, vans, and light trucks.
• The Second Letter (e.g., N, M, L, K, J, G): Shows the oil's performance tier; newer letters (SP > SN > SM > SL > SJ) mean better protection and features like:
  • API SP (Latest): Protects against Low-Speed Pre-Ignition (LSPI), timing chain wear, and high-temperature deposits.
  • API SN: Good for 2020 and older engines, better high-temp/sludge protection than older specs.
  • API SM/SL/SJ: Older standards for earlier engine models, but higher specs are backward compatible.