Most of the car manufacture gave lower rate than car loan in Bank. The 0% for big three, 2-3^ for Toyota, the only exception probably is Honda.
If you apply for car loan in the bank, the interst rate is not low. Unless you can use your LOC.
rate of personal car loan with your home bank is prime + 1.5.
and Line of credit is prime + 2.0.
For example, the prime is 4.5% now, your car loan is 6%, and LOC is 6.5%.