Good question! There is no simple answer though. I have seen no difference in my scores after paying months on end on my installment loans. In fact when I had one paid off, my scores hardly changed. Others have posted increases and decreases in their scores after paying off an installment account. Went it comes to amounts owed (utilization), revolving util (amount owed) carries a lot more weight than installment util (amount owed). It's far worse to have revolving balances reporting 80% util than it does to have installments balances reporting 80% of the original loan amount. It's not even close!
My question is: As the balance of an installment (auto) loan is reduced each month does it impact the FICO scoring model subsection titled "Amounts owed", which accounts for 30% of my score, in a positive manner? It seems logical to me, does anyone know reality?