![From my understanding, the second number is the viscosity at running temp, so how come 5W-30 and 10W-30 don't go up to the same temperature? : r/MechanicAdvice From my understanding, the second number is the viscosity at running temp, so how come 5W-30 and 10W-30 don't go up to the same temperature? : r/MechanicAdvice](https://preview.redd.it/gddasdse4mb81.png?width=640&crop=smart&auto=webp&s=3085084e44862410f299babb0cddd5460794f771)
From my understanding, the second number is the viscosity at running temp, so how come 5W-30 and 10W-30 don't go up to the same temperature? : r/MechanicAdvice
Does it really matter what type of oil you put in your car during the summer vs winter? 5W-30 vs 10W-40. - Quora
![Engine Oil Codes Explained, SAE (Society of Automotive Engineers) numbers - Oil Viscosity Explained - YouTube Engine Oil Codes Explained, SAE (Society of Automotive Engineers) numbers - Oil Viscosity Explained - YouTube](https://i.ytimg.com/vi/Hb6CX_rWoIA/mqdefault.jpg)