I have a 98 Mazda B 4000 with 78000 miles on it. I have used M1 10W 30 and Motorcraft oil filters since the first oil change at 4000 mile intervals. Lately I have being putting about 5000 miles per year out of which 2000 of those miles are towing 3000lbs in Florida during the summer months. How often should I change the oil and should I use another filter or oil weight? Any other suggestions?
Thanks for your answers.