I've been confused for years about using lower viscosity oils in the winter. Is the lower "w" winter number the only thing that counts? My truck using a 22RE engine is usually preferred to run higher viscosity oils once at operating temp (up to 15w-50 in some cases). Unless the air is so cold the engine never gets to full operating temp, shouldn't the second number not matter at all in terms of the season? I should go with a 5w-40 in the winter instead of 5w30? Summer is a 10w-40 oil. It doesn't get cold enough here to prevent an engine from reaching operating temp, and if it did, I would just block the radiator with cardboard.
With modern synthetics, is the lower W number the only thing that counts for winter? Back in the day, one would be using a conventional oil that can't span such a wide range of viscosity attributes and you had no choice but to lower the operating temp viscosity in order to have something that was better flowing on really cold starts.
With modern synthetics, is the lower W number the only thing that counts for winter? Back in the day, one would be using a conventional oil that can't span such a wide range of viscosity attributes and you had no choice but to lower the operating temp viscosity in order to have something that was better flowing on really cold starts.
