I just checked my records for the last time I changed the oil in my '98 Ford F150 W/4.6L. I usually change every 6 mo. but so far in just over 4 mo. I only have about 1300 mi on this change. Most of my driving is short trips in a small town with a 40-50 mi. trip approx. every 2 wks. I use Havoline 5w30 and a Pure One filter each time. The total miles on the truck is 70,300. Do you think I can run this until spring? I live in Tennessee, so it's not as if the weather was a big factor. I'll use it a few times when the temp. is below freezing but not often. Comments?