Although 10W rated down to 0 degrees F. , parity for cold engine starts ended below about 25 degrees F. between 10W and 5W .
Below 25 degrees F . the 5W pulled away with respect to lower time before oil reached critical engine parts ... Because cold engine starts are a cumulative effect , my cut off temp for running a 10W oil is approx. 25 degrees F . *We are talking fractions of a second for differences in cold start difference between 10W and 5W at 25 degrees F. so in real life the 0 degrees F. cut off would probably serve you well - conversely , if you have a choice of 5W 30 why mess with 10W 30 ? Back in the day there were no options for 10W30 - today there is ...
Below 25 degrees F . the 5W pulled away with respect to lower time before oil reached critical engine parts ... Because cold engine starts are a cumulative effect , my cut off temp for running a 10W oil is approx. 25 degrees F . *We are talking fractions of a second for differences in cold start difference between 10W and 5W at 25 degrees F. so in real life the 0 degrees F. cut off would probably serve you well - conversely , if you have a choice of 5W 30 why mess with 10W 30 ? Back in the day there were no options for 10W30 - today there is ...
