Mobil 1 oil filters - new design
"The M1-111 is a filter that was designed for 15,000 mile change intervals. It is being phased out and replaced with the M1-111A. This new filter has improved rubber compounds in the valving and seal areas. This change creates a filter that can be used up to a 20,000 mile change interval. The filtration of both filter is the same quality but with the improvement of the seal and valving the extended change interval is accomplished. Let me know if you have any other questions, thank you."
I wanted to know what the difference was between the old and new design so I submitted my question to Mobil 1 Tech Support. Just thought I'd share what they said. Based on their reply I'll purchase the updated design.
2008 Voyage 35L, Allison 6 speed auto and GM Workhorse 8.1 gas